18 Apr 2022

Samacheer Kalvi 9th Science Book Back Unit 6 Term 1

Samacheer Kalvi 9th Term I Science Book Back Question and Answers – Unit 6:

Samacheer Kalvi 9th Standard New Science Book Back 1 Mark and 2 Mark Question & Answers PDF uploaded and available below. Class 9 New Syllabus 2021 to 2022 Book Back Ques & Ans solutions available for both English and Tamil Medium. Class 9 Science Book Term 1 Unit 6 – Living World of Plants – Plant Physiology Answers/Solutions are provided on this page. 9th Std Science Book is of Term 1st, 2nd, 3rd, and consists of 9 Units in each Term. All 9 Units of Term 1st, 2nd, 3rd Science Book Back One, and Two Mark Solutions are given below.

Check Unit wise and  9th New Science Book Back Question and Answers Guide/Solutions PDF format for Free Download.English, Tamil, Maths, Science, and Social Science Book Back Questions and Answers available in PDF. Check Science – Physics, Chemistry, and Biology, Social Science – History, Geography, Civics, Economics below. See below for the Samacheer Kalvi 9th Science Book Back Unit 6 Term 1 PDF:

Samacheer Kalvi 9th Science Book Back Unit 6 Term 1 Solutions Guide PDF:

Science Subject 1 Mark and 2 Mark Solutions Guide PDF available below. Click the Download option to download the book back 1 Mark & 2 Mark questions and answers. Take the printout and use it for exam purposes.

Term – 1

Unit – 6

Living World of Plants – Plant Physiology

I. Multiple choice Questions:

1. A big tree falls in a forest but its roots are still in contact with the soil. The branches of this fallen tree
straight up. This happens in response to …………
a) water and light
b) water and minerals
c) gravity and water
d) light and gravity

2. The tropic movement that helps the climbing vines to find a suitable support is …………
a) phototropism
b) geotropism
c) thigmotropism
d) chemotropism

3. The chemical reaction occurs during photosynthesis is …………..
a) CO2 is reduced and water is oxidized
b) water is reduced and CO2, is oxidized.
c) both CO2 and water are oxidized
d) Both CO2 and water are produced

4. Transpiration is best defined as …………..
a) loss of water by the plant
b) evaporation of water from the aerial surfaces from the plant.
c) loss of water in the form of water vapour from the underground parts of the plant body
d) release of water from the plant into the atmosphere

II. State whether the following statements are true or false. If false, write the correct sentence:

1. The response of plant to the chemical stimulus is called phototropism.
Ans: False – Chemotropism.

2. Shoot is positively phototropic and negatively geotropic.
Ans: True

3. Scientific term used to represent the bending of roots towards water is called geotropism.
Ans: False – Hydrotropism

4. Joseph priestley devised an experiment to find out that water alone was the cause of the increase in the weight of the plant.
Ans: False – it was VanHelmont who thought that water alone was the cause of the increase in weight of the plant.

5. When the weather is hot water evaporates lesser which is duet o opening of stomata.
Ans: False – When the weather is hot water evaporates more which is due to opening of stomata.

III. Fill in the blanks:

1. The shoot system grows upward in response to Phototropism
2. Root is positively hydrotropic as well as positively geotropic.
3. The green pigment present in the plant is ChlorophyII
4. The minerals like nitrogen, potassium and phosphorus are required in substantial quantity by the plants are called Macronutrients

IV. Match the following

9th science book back questions with answer

Ans: 1 –d; 2 –a; 3- b; 4 –c

V. Analog

1. Towards a stimulus : ………………
Away from the stimulus : Negative tropism

2. Hydrotropism : Response towards
Water phototropism : …………………

3. Photosyntheiss : ………………….
Transpiration : Stomata
Ans: 1) Positive Tropism         2) Response towards light      3) ChlorophyII

VI. Short Answer:

1. Give an example for a plant whose leaf shows a mesmerizing movement.
Ans: Desmodium gyrans (Indian Telegraph plant)

2. Write the scientific terms used to represent the following:
a) Growing of roots towards the gravity.
b) Bending of roots towards the water.
a) positive geotropism and positive hydrotropism – root.
b) Positive phototropism – stem

VII. Answer the following in one or two sentences

1. What is nastic movement?
Ans: Some movements in plants not directed towards stimuli is known as Nastic movement.

2. Name the plant part.
a) Which bends in the direction of gravity but away from the light?
Ans: root

b) Which bends towards light but away from the force of gravity?
Ans: Shoot

3. Differentiate Phototropism from Photonasty

Phototropism Photonasty
1) Unidirectional, response to the stimulus of


1) Non directional response to the stimulus of light.
2) Growth dependent movement 2) Growth independent movement
3) Permanent and irreversible. 3) Temporary and reversible
4) Slow action

Eg. Growth of stem towards light

4) Immediate fast action

Eg. Unfolding of Dandelion flower in the morning and closing in the evening.

4. Photosynthesis converts energy X into energy Y
a) What are X and Y
Ans: X – Solar energy; Y- Chemical energy

b) Green plants are autotrophic in their mode of nutrition, why?
Ans: Green plants have green pigment, so can prepare food directly from sunlight using CO2 and H2O as raw material. Almost all the organisms rely on plant for their food – so green plants are autotrophic.

5. Define Transpiration.
Ans: The loss of water in the form of water vapour from the aerial parts of the plant body is called Transpiration.

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