General Science 7th Class Chapter 12 Earth and Space Solved Exercise

 

General Science

7th Class

Chapter 12

Earth and Space

Questions

12.1 Encircle the correct option.

1. An object is attracted towards the Earth due to:

a. pull        b. push        c. gravity        d. friction

2. Which of the following is the major cause of tides?

a. heating oceans by the Sun

b. gravitational pull of the Moon

c. earthquakes on the surface of the ocean floor

d. change in  the wind direction

3. Seasons on the Earth's surface are caused by:

a. spin motion of the Earth about its own axis

b. orbital motion of the Earth around the Sun

c. tilt of Earth on its axis

d. the tilt of Earth and orbital motion of the Earth around the Sun

4. What is the season on 22nd June in the southern hemisphere?

a. spring        b. autumn        c. summer        d. winter

5. The weight of an object on Earth's surface is 600 N. What will be its weight on the Moon's surface?

a. 600 N        b. 300 N        c. 200 N        d. 100 N

6. The tides are highest during:

a. day        b. night        c. half Moon        d. full Moon

12.2 Write short answers.

1. An athlete can jump 5 metre up on the Earth, how high he can jump on the Moon?

Ans.

The force of gravity on Moon surface is 1/6 of that on Earth. If an athlete jumps 5 metre high on Earth, he can jump 30 metres on the Moon.

2. A person can throw a shot put 2 meters away. How long will be his throw on the Moon's surface?

Ans.

If a person can throw a shot 2 metres away at the earth surface, his throw on the moon surface will be 12 metres.

3. Which of the Sun or Moon has a greater pull on the ocean's water? Give reason of your answer.

Ans.

Moon has greater pull on oceans water than that of sun. The reason is that moon is nearer to earth surface than sun.

4. Differentiate force exerted by the Moon on the waters at the near surface and that exerted on the water of far surface.

Ans.

On the near side of Earth, (the side facing moon) the gravitational force of the moon pulls the ocean's water towards it, creating on bulge. On the far side of the Earth, inertia dominates, creating a second bulge. In this way, two bulges of water are formed.

5. What will be the season in Australia when there is summer in Pakistan?

Ans.

Pakistan is in northern hemisphere, and Australia is in Sothern hemisphere. If there is Summer in Pakistan, there will be winter in Australia.

General Science 7th Class Chapter 11 Technology in Everyday Life Solved Exercise

General Science

7th Class

Chapter 11

Technology in Everyday Life

Questions

11.1 Encircle the correct option.

1. Conservation of water means

a.  a using water        b. save water        c. avoiding water        d. wasting water

2. While preparing pickles, which is not used as preserving agent:

a. honey        b. salt        c. vinegar        d. pepper

3. Which is not used in making mango pickle?

a. mango slices        b. honey        c. table salt        d. turmeric powder

4. Which is not used in the preparation of lemon prickle?

a. lemon        b. sugar        c. acetic acid        d. tea leaves

5. Which is not used in the preparation of orange juice?

a. garlic        b. orange        c. sugar        d. water

11.2 Write short answers.

1. What type of irrigation is more beneficial either drip or sprinkler?

Ans.

  Drip irrigation is more beneficial than other types.

2. List the ingredients required for preparation of mango pickle.

Ans.

Unripened mangoes, pickle jar, salt vinegar (preservative agent) mustard seeds etc.

3. What are the ingredients required for preparation of onion pickle.

Ans.

2 cinnamon sticks, 6 whole cloves, pinch crushed red pepper flakes. Freshly squeezed lime juice.

4. Name the ingredients required for preparation of lemon pickle.

Ans.

Lemon cut into circular slices, 1/2 kg sugar 1/2 cup, Acetic acid 1 cup.

5. State the ingredients required for preparation of orange juice.

Ans.

Orange slice, salt, juicer blender, knife, strainer, bowl.

General Science 7th Class Chapter 10 Heat and Temperature Solved Exercise

General Science

7th Class

Chapter 10

Heat and Temperature

Questions

10.1 Encircle the correct option.

1. The degree of hotness or coldness is called:

a. thermal contraction        b. thermal expansion        c. temperature        d. heat

2. The bulb of the thermometer is filled with:

a. oil        b. alcohol        c. water        d. salt

3. Centigrade scale is also called:

a. Fahrenheit scale        b. Kelvin scale        c. Absolute scale        d. Celsius scale

4. The temperature of boiling water in centigrade scale is:

a. 0˚ C       b. 32˚ C        c. 37˚ C        d. 100˚ C

5. The temperature of melting ice in Fahrenheit scale is

a. 0˚ F       b. 32˚ F        c. 100˚ F        d. 212˚ F

6. When a 10 cm iron rod is heated to high temperature:

a. its volume decreases        b. its volume increases

c. its density remains the same        d. none of these

7. The average energy due to movement of molecules in a substance is called:

a. potential energy        b. electric energy        c. kinetic energy        d. chemical energy

8. The energy that transfers from one object to another due to the temperature difference is called:

a. atomic energy        b. heat energy        c. light energy        d. sound energy

9. The gaps are left after every few minutes in the railway tracks, so that:

a. they cannot be de-tracked in summer due to expansion

b. they cannot be de-tracked in winter due to expansion

c. they cannot be de-tracked in summer due to contraction

d. they cannot be de-tracked at night due to contraction

10. The rise of liquid in the thermometer is due to:

a. evaporation        b. contraction        c. expansion        d. sublimation

11. The contraction of the objects on cooling is due to:

a. reduction in size of the particles        b. increase in size of the particles

c. increase in inter particle distances        d. decrease in inter particle distances

12. An empty steel container is sealed and heated, which of the following properties of the gas is likely to increase?

a. mass        b. pressure        c. volume        d. density

10.2 Give short answers.

1. Define heat.

2. Name three modes of heat transfer.

3. Which two temperatures are the base of Celsius and Fahrenheit temperature scales?

4. Give five examples of good conductors of heat.

5. Give five examples of bad conductors of heat.

1. Define heat.

Ans.

Heat is the measure of thermal energy of a substance. It is the total kinetic energy of all the particles of a substance.

2. Name three modes of heat transfer.

Ans.

Three modes of heat transfer are the following:

1. Conduction        2. Convection        3. Radiation

3. Which two temperatures are the base of Celsius and Fahrenheit temperature scales?

Ans.

Melting point and boiling point of water are two temperatures which are base of temperature scales.

4. Give five examples of good conductors of heat.

Ans.

Five good conductors of heat are Iron, Copper, Silver, Aluminum and Gold.

5. Give five examples of bad conductors of heat.

Ans.

Five bad conductors are wood, rubber, glass, mica and cotton.

General Science 7th Class Chapter 9 Waves and Energy Solved Exercise

 General Science

7th Class

Chapter 9

Waves and Energy

Questions

9.1 Encircle the correct option.

1. Sound waves are not:

a. compressional waves        b. transverse waves

c. mechanical waves        d. low frequency waves

2. Sound cannot pass through:

a. solid        b. liquid        c. gasses        d. vacuum

3. The speed of sound in air is:

a. 100 m/s        b. 340 m/s        c. 1000 m/s        d. 330 km/s

correct 300 on guide

4. Which of the following animals can respond to lowest frequency?

a. cat        b. cow        c. dog        d. elephant

5. Which of the following animals can respond to highest frequency?

a. bat        b. cat        c. frog        d. dolphin

6. Which have audible range for 2k Hz and 120k Hz?

a. human        b. owl        c. bat        d. dolphin

7. Which of the following features is the height of the wave from the rest position or midline?

a. frequency        b. amplitude        c. pitch        d. wavelength

8. Which of the following features of a wave is the number of waves that pass by each second?

a. loudness        b. amplitude        c. frequency        d. wave speed

9. What is transferred by the movement of waves?

a. matter        b. energy        c. nothing        d. both the matter and energy

10. What type of wave does not need matter to travel through?

a. mechanical        b. electromagnetic        c. sound        d. transverse

11. Which sequence of visible colour is correct from longest wavelength to short wavelength?

a. violet, indigo, blue, green, orange, yellow, red

b. red, orange, yellow, green, blue, indigo, violet

c. red, yellow, green, orange, violet, blue, indigo

d. red, yellow, green, orange, violet, indigo, blue

9.2 Define the following:

1. Wave

2. Electromagnetic wave

3. Wavelength

4. Frequency

5. Amplitude

6. Time period

1. Wave

Ans:

A wave is a disturbance or variation that transfers energy progressively from point to point in a medium.

2. Electromagnetic wave

Ans:

Waves which do not require any medium to travel through is called electromagnetic waves. Light waves are the examples of electromagnetic waves.

3. Wavelength

Ans:

Wavelength is the distance between the centres of the compressions or rarefactions of two consecutive waves.

4. Frequency

Ans:

Frequency is the number of waves produced in one second. It is equal to the number of times a body vibrates in one second. Frequency of wave is represented by "f".

5. Amplitude

Ans:

The maximum displacement of the vibrating objects from its mean position is called its amplitude. It is measured in the unit 'metre (m)'.

6. Time period

Ans:

The time during which a body completes one wave cycle is called the time period. It is represented by T.

General Science 7th Class Chapter 8 Force and Motion Solved Exercise

General Science

7th Class

Chapter 8

Force and Motion

Questions

8.1 Encircle the correct option.

1. An example of contact force:

a. electrostatic force        b. muscular force

c. magnetic force        d. gravity

2. The force between two negatively charged particles is:

a. gravitational        b. frictional        c. repulsion        d. attraction

3. Which statement is true?

a. for every action force, there is a smaller reaction force in the opposite direction

b. for every action force, there is a smaller reaction force in the same direction

c. for every action force. there is an equivalent reaction force in opposite direction

d. for every action force, there is an equivalent reaction force in the same direction

4. The Earth's pull on the objects is called:

a. gravity        b. frictional force        c. electrostatic force        d. magnetic force

5. A batsman hits the ball back towards the bowler, which effect of force is seen:

a. change of shape        b. change of direction

c. change of state from motion to rest        d. change of state from rest to motion

6. Which one of the following statements is correct?

a. 1m = 1000 km        b. m/s is the unit of displacement

c. N is the unit of force        d. 1hr = 60s

7. Which one of the following statements is not correct?

a. Displacement is the shortest distance between two points

b. Displacement is the distance covered in one second

c. Meter (m) is the unit of displacement

d. Rate of change of distance with time is called speed

8.2 Define the following:

1. Contact forces

2. Non-contact forces

3. Gravitational force

4. Displacement

5. Speed

1. Contact forces

Ans.

Contact forces are those forces that act only when objects are in physical contact with other objects and bring about necessary changes.

Examples: muscular force, frictional force

2. Non-contact forces

Ans.

Some forces do not involve physical contact between the objects on which they act. They act through the space between them. Such forces are called non-contact forces.

Examples: Magnetic force, electrostatic force and gravitational force.

3. Gravitational force

Ans.

The force due to which every body of the universe attracts every other body is called force of gravitation.

4. Displacement

Ans.

Displacement is defined as the shortest distance between two points.

5. Speed

Ans.

Speed is defined as the distance travelled per unit time.

Speed = Distance / time

General Science 7th Class Chapter 7 Solutions Solved Exercise

General Science

7th Class

Chapter 7

Solutions

Questions

7.1 Encircle the correct option.

1. Which of the following is insoluble in water?

a. sodium chloride        b. oil        c. table salt        d. baking powder

2. A solution to which no more solute can be dissolved at a particular temperature is called:

a. dilute solution        b. concentrated solution

c. saturated solution        d. unsaturated solution

3. A concentrated solution can dissolve in it:

a. no further amount of solute

b. less quantity of solute

c. large quantity of solute

d. amount of solute equal to the amount of solvent

4. Amount of solute required to saturate 100g of solvent at a particular temperature is called:

a. molarity        b. molality        c. normality        d. solubility

5. A solution having relatively less amount of solute dissolved in it is called:

a. dilute solution        b. binary solution

c. concentrated solution        d. saturated solution

7.2 Define the followings:

1. Binary solution

2. Aqueous solution

3. Solute

4. Homogeneous mixture

5. Unsaturated solution

1. Binary solution

Ans.

A solution which is prepared at by mixing only two substances, is called binary solution.

2. Aqueous solution

Ans.

A solution in which water is used as solvent is called aqueous solution.

3. Solute

Ans.

Component of solution present in smaller quantity is called solute.

4. Homogeneous mixture

Ans.

Mixture having same composition in its all parts is called homogenous mixture.

5. Unsaturated solution

Ans.

Solution to which further amount of solute can also be dissolved at a particular temperature is called unsaturated solution.

General Science 7th Class Chapter 6 Chemical Bonds Solved Exercise

General Science

7th Class

Chapter 6

Chemical Bonds

Questions

6.1 Encircle the correct option.

1. A molecule consists of two or more

a. compounds        b. atoms        c. formulae        d. elements

2. Which of the following is a cation?

a. H₂        b. H₂O       c. CO₂       d. NH⁺⁴

3. Which of the following is an anion?

a. F        b. Cl        c. S^2-       d. NH₃

4. Oxygen is a:

a. monovalent element        b. divalent element

c. trivalent element        d. tetravalent element

5. Chemical bond between N₂ molecule is:

a. ionic        b. single covalent        c. double covalent        d. triple covalent

6. How many atoms from one molecule of chlorine gas?

a. 1        b. 2        c. 3        d. 4

7. Outermost shell of sodium atom has _________ electron (s):

a. 1        b. 2        c. 3        d. 4

8. Outermost shell of chlorine atom has ________ electron(s):

a. 1        b. 2        c. 6        d. 7

9. Which of the following has stable electronic configuration?

a. H        b. He        c. C        d. Li

10. Which of the following has double covalent bond?

a. Br₂        b. CO₂       c. HCl       d. N₂ 

6.2 Define the following and explain with examples:

1. Valency

2. Ion

3. Formula

4. Bond

5. Electronic configuration

1. Valency

Ans.

The combining capacity of atoms with other atoms is called valency.

Example: Valency of oxygen is 2 as it combines with two hydrogen atoms to from H₂O

2. Ion

Ans.

The charged particles (atom or group of atoms) are called ion.

Example: Na⁺ is an atom having charge on it while HSO₄^- is a group of atoms having charge on it, both Na⁺ and HSO₄^- are ions.

3. Formula

Ans.

A symbolic representation of an element or compound is called formula.

Example: Formula of oxygen is O₂and sulphuric acid is H₂SO₄

.

4. Bond

Ans.

The force of attraction that holds stoms to together in a substance is called bond.

Example: Bond is present in NaCl which bond Na⁺ and Cl^- together.

5. Electronic configuration

Ans.

The distribution of electrons in the shells around nucleus of an atom is called electronic configuration.

Example: Electronic configuration of Lithium (Li) is 1s² 2s¹.

General Science 7th Class Chapter 5 Physical and Chemical Changes Solved Exercise

General Science

7th Class

Chapter 5

Physical and Chemical Changes

Questions

5.1 Encircle the correct option.

(i) Three of the following are alike. Select the one that is different from the others.

a. Solubility        b. Conductance        c. Oxidation        d. Boiling of a substance

(ii) A physical change occurs when:

a. Iron rusts        b. Solution of common salt is heated

c. A piece of wood burns        d. Sugar is heated strongly

(iii) A gas produced on heating solid potassium chlorate is:

a. Hydrogen        b. Carbon dioxide        c. Methane        d. Oxygen

(iv) Select all that happen during a chemical change.

a. A temporary change occurs

b. Composition of the substances is changed

c. Properties of the substances are changed

d. New substances with different properties are formed

(v) Freezing of a liquid is a:

a. Chemical change        b. chemical property        c. physical change        d. None of above

(vi) What are the products when electric current is passed through water?

a. only steam        b. hydrogen and steam        c. hydrogen and oxygen        d. oxygen and steam

(vii) A piece of iron is kept in open air for 5 days. A film of corrosion formed over it is:

a. iron oxide        b. iron sulphide        c. iron chloride        d. iron hydride

(viii) During combustion, a substance reacts with:

a. hydrogen        b. water        c. carbon dioxide        d. oxygen

(ix) The temperature at which a liquid's vapour pressure is equal to the external pressure surrounding the liquid is:

a. melting point        b. boiling point        c. freezing point        d. highest temperature

(x) Silver + Hydrogen sulphide + Oxygen → Silver sulphide + water

      The above reaction is known as:

a. combustion        b. rusting        c. tarnishing        d. dehydration

5.2 Define the following:

1. Physical change

2. Chemical change

3. Physical property

4. Chemical property

5. Melting point

6. Freezing point

7. Boiling point

8. Solubility

9. Rusting

10. Tarnishing

1. Physical change

Ans.

A change in the physical properties of a substance is called physical change.

2. Chemical change

Ans.

A change in the chemical properties of a substance is called chemical change.

3. Physical property

Ans.

A property due to the physical behaviour of the substance is called physical property.

4. Chemical property

Ans.

A property associated with the chemical structure of the substance is called chemical property.

5. Melting point

Ans.

Melting point is the specific temperature of a solid at which, it begins to melt.

6. Freezing point

Ans.

The temperature at which a liquid starts changing into solid is called freezing point.

7. Boiling point

Ans.

The specific temperature for a liquid at which, it begins to boil and converts from liquid state to gaseous state.

8. Solubility

Ans.

Solubility is the ability of a substance the (solute), to form a solution with another substance the (solvent).

9. Rusting

Ans.

It is a chemical change during which oxygen in the moist air reacts with the iron (Fe) to convert it into iron oxide (rust).

10. Tarnishing

Ans.

It is formation of thin film of corrosion that forms on the surface of objects made of silver, copper, brass, aluminum, magnesium, etc.

General Science 7th Class Chapter 4 Structure of an Atom Solved Exercise

General Science

7th Class

Chapter 4

Structure of an Atom

Questions

4.1 Encircle the correct option.

1. An element with fifteen protons in its atomic nucleus has atomic number:

a. 5        b. 10        c. 15        d. 20

2. The central part of an atom is called:

a. electron        b. proton        c. neutron        d. nucleus

3. Letter K is used to express the ________ shell around the nucleus of an atom.

a. 1st        b. 2nd        c. 3rd        4. 4th

4. The total number of electrons which M shell can a accommodate:

a. 2        b. 8        c. 18        d. 32

5. The particle of an atom having negative charge on it:

a. electron        b. proton        c. neutron        d. nucleus

6. Atomic number of element present in period 2 and group 15 of the Periodic Table:

a. 4        b. 5        c. 6        d. 7

7. How many periods are there in the Periodic Table?

a. five        b. six        c. seven        d. eight

8. Formula showing maximum number of electrons in a shell:

a. n²        b. 2n²        c. 3n²        d. 4n²

9. The mass of an atom is almost due to the:

a. electrons        b. protons        c. neutrons        d. nucleus

10. The particles of an element having different mass numbers:

a. protons        b. neutrons        c. atoms        d. isotopes

4.2 Give short answers.

i. What is atom?

Ans.

An atom is the smallest particle of an element that takes part in a chemical reaction.

ii. Define element.

Ans.

Element is a substance which is made up of same type of atoms.

iii. What type of charge is present on neutron?

Ans.

Neutrons are neutral particles. They have no charge on them.

iv. What do you mean by atomic number?

Ans.

The number of protons present in an atom of an element is called atomic number of that element. It is donated as Z.

v. What is mass number?

Ans.

The total number of protons plus neutrons present in an atom of an element is called mass number of that element. It is donated as A.

General Science 7th Class Chapter 3 Immunity and Diseases Solved Exercise

General Science

7th Class

Chapter 3

Immunity and Diseases

Questions

3.1 Encircle the correct option.

1. A pigment in the skin that protects harmful effects of sunlight:

a. melanin        b. haemoglobin        c. lymphocyte        d. lysozyme

2. Hydrochloric acid is found in:

a. saliva        b. gastric juice        c. bile        d. pancreatic juice

3. ________ is the inflammation of liver.

a. tuberculosis        b. typhoid        c. COVID-19        d. hepatitis

4. Billions of new blood cells are produced daily in:

a. heart        b. lever        c. spleen        d. bone-marrow

5. Nuclear membrane is not found in:

a. plant cell        b. animal cell        c. bacterial cell        d. fungal cell

3.2 Give short answers.

i. Define the following:

(a) Pathogen

(b) Antigen

(c) Infection

(d) Phagocytosis

Ans.

(a) Pathogen

Microorganisms that cause diseases in human body are called pathogen.

(b) Antigen

An antigen is a toxin or other foreign substances which induces an immune response in the body, the production of antibodies.

(c) Infection

Entry and growth of microorganisms into our body called infection.

(d) Phagocytosis

Phagocytosis is a cellular process of ingesting and eliminating foreign substances and microorganisms.

General Science 7th Class Chapter 2 Human Respiratory and Circulatory Systems Solved Exercise

General Science

7th Class

Chapter 2

Human Respiratory and Circulatory Systems

Questions

2.1 Encircle the correct option.

1. Exchange of gases takes place in:

a. lungs        b. bronchioles        c. alveoli        d. blood

2. Trachea divides into two:

a. bronchi        b. veins        c. villi        d. ribs

3. The part of the heart which receives blood from lungs:

a. left atrium        b. right atrium        c. left ventricle        d. right ventricle

4. Left atrium opens into:

a. Right atrium        b. right ventricle        c. left ventricle        d. aorta

5. Right atrium receives:

a. oxygenated blood        b. deoxygenated blood        c. both types of blood        d. no blood

6. Blood vessels that carry blood away from the heart are:

a. capillaries        b. veins        c. arteries        d. venules

7. Aerobic respiration takes place in:

a. mitochondria        b. chloroplasts        c. nucleus        d. blood vessels

8. Products of anaerobic respiration in yeasts are _________ along with energy:

a. carbon dioxide and water        b. ethanol and carbon dioxide

c. oxygen and water        d. lactic acid and water

9. Exchange of material in the body tissues and blood takes place in:

a. aorta        b. ventricles        c. veins        d. capillaries

10. Which of the following plays an important role in blood clotting?

a. red blood cells        b. white blood cells        c. platelets        d. bone cells

2.2 Differentiate between:

1. Aerobic and anaerobic respiration

Ans:

Aerobic Respiration:

• It takes place in the presence of oxygen
• Large amount of energy is released in aerobic respiration
• Carbon dioxide and water are the products of aerobic respiration

Anaerobic Respiration:

• It takes place in the absence of oxygen
• Small amount of energy is released in anaerobic respiration
• Lactic acid is produced in muscle. Ethanol and carbon dioxide are produced in yeast

2. Oxygen and carbon dioxide

Ans:

Oxygen:

     In animals, oxygen is very important for the process of aerobic respiration. In result,             large amount of energy is released in organism's body. Organisms inhale oxygen from         environment.

Carbon dioxide:

     Carbon dioxide is the by product of respiration and it is exhaled from lungs by animals         and in plants by stomata.

3. Breathing and respiration

Ans:

Breathing:

• Breathing is the exchange of gases by inhalation and exhalation of the air.
• It takes place in alveoli of the lungs.
• The purpose of breathing is to provide oxygen to all the body cells and getting rid of carbon dioxide produced in the cells.

Respiration:

• Respiration is a process to release energy from food during a series of reaction, each of which is catalyzed by specific enzymes.
• It takes place in mitochondria of the cells.
• The purpose of respiration is to provide energy to the whole body for carrying on the activities of life.

4. Arteries and Veins

Ans:

Arteries:

• Carry blood away from the heart
• Thick walled vessels
• Facing high blood pressure
• having no valves
• Carry blood having oxygen and nutrients for the body cells, except pulmonary artery which carries deoxygenated blood.

Veins:

• Carry blood towards the heart
• Thin walled vessels
• Facing low blood pressure
• Veins have valves
• Return blood carrying carbon dioxide and other wastes, except pulmonary vein which carries oxygenated blood.

5. Capillaries and alveoli

Ans:

Capillaries:

    Capillaries provide surface area for exchange of materials between the body cells and blood cells.        They provide oxygen and nutrients to the cells and collect carbon dioxide and other wastes from the     cells.

Alveoli:

    In lungs, each bronchiole ends in a group of air sacs or alveoli. The lungs look like sponges due to        the presence of alveoli. Millions of alveoli are found in the lungs. They are surrounded by thick            network of blood capillaries.

2.3 Give short answers.

i. Name the body parts involved in breathing system.

Ans.

1. Nose or Mouth

2. Trachea

3. Bronchus

4. Bronchiole

5. Alveolus in lung

6. Blood Capillaries

ii. Name the products of anaerobic respiration which occurs in muscles.

Ans.

Lactic acid is the product of anaerobic respiration which occurs in muscle.

iii. Name different blood cells.

Ans.

(i) Red blood cells (RBCs)

(ii) White blood cells (WBCs)

(iii) Platelets

iv. Where does blood oxygenate?

Ans.

Blood is oxygenated by alveoli in the lungs.

v. Name different chambers of human heart.

Ans.

Human Heart has following chambers:

1. Right atria

2. Left atria

3. Right ventricle

4. Left ventricle

General Science 7th Class Chapter 1 Plant Systems Solved Exercise

General Science

7th Class

Chapter 1

Plant Systems

Questions

1.1 Encircle the correct option.

(i) Water and dissolved salts are conducted from roots to leaves by:

a. root hairs        b. xylem        c. phloem        d. stomata

(ii) The innermost layer of cortex in the root:

a. epidermis        b. endodermis        c. pericycle        d. cambium

(iii) What is required for photosynthesis in addition to light?

a. oxygen and carbon dioxide            b. oxygen and water

c. carbon dioxide and water            d. nitrogen and water

(iv) Oxygen and ________ are the products of photosynthesis:

a. water        b. carbon dioxide        c. glucose        d. chlorophyll

(v) The products of respiration are carbon dioxide and:

a. water        b. oxygen        c. mitochondria        d. chloroplast

(vi) The loss of water from aerial parts of the plants:

a. respiration        b. photosynthesis        c. evaporation        d. transpiration

(vii) Chlorophyll is present in:

a. mesophyll cells        b. upper epidermis        c. lower epidermis        d. endodermis

(viii) Mineral required in the formation of chlorophyll:

a. iodine        b. iron        c. phosphorus        d. magnesium

(ix) The force between the molecules of water:

a. adhesive force        b. cohesive force        c. repulsive force        d. magnetic force

(x) Rate of transpiration decreases with the increase of:

a. temperature        b. light intensity        c. humidity in air        d. wind speed

1.2. Write short answers.

i. What is primary root?

Ans.

The initial root which grows from radicle of the embryo is the primary root or also called as tap root.

ii. What is secondary root?

Ans.

The branches of primary roots are called secondary roots.

iii. State the function of root cap.

Ans.

Root cap protects the newly born soft cells from being damaged and environmental stresses. It enables root tip to grow through soil.

iv. Write word equation for photosynthesis.

Ans.

Carbon dioxide + Water + Sunlight energy → Food (Glucose) + Oxygen

v. Write word equation for respiration.

Ans.

Food (Glucose) + Oxygen → Carbon dioxide + Water + Chemical energy