Life Processes in Plants — Hard

Q1. Assertion (A): In Activity 10.1, the plant in Pot B (direct sunlight, no water) is likely to die. Reason (R): Sunlight alone, without water, is sufficient for a plant to carry out photosynthesis.

• A. Both A and R are true, and R is the correct explanation of A.
• B. A is true, R is false.
• C. Both A and R are true, but R is NOT the correct explanation of A.
• D. A is false, R is true.

Q2. Question 4 of the chapter asks: 'Does the broad and flat structure of leaves make plants more efficient for photosynthesis?' The best justification is that a broad and flat leaf

• A. Exposes a large surface area to sunlight and contains many stomata for gas exchange
• B. Stores more water than a narrow leaf
• C. Has a larger root system attached to it
• D. Makes the plant taller and stronger

Q3. Assertion (A): In Activity 10.3, the leaf taken from the plant kept in the dark for 36 hours does not turn blue-black anywhere with iodine. Reason (R): In the absence of sunlight, even chlorophyll-containing green patches cannot prepare starch.

• A. Both A and R are true, but R is NOT the correct explanation of A.
• B. A is true, R is false.
• C. Both A and R are true, and R is the correct explanation of A.
• D. A is false, R is true.

Q4. Statements about Activity 10.4: I. The plant is kept in the dark for two to three days to destarch it. II. Caustic soda absorbs carbon dioxide. III. The leaf-part inside the bottle turns blue-black with iodine. Which statements are correct?

• A. I and III only
• B. II and III only
• C. All three
• D. I and II only

Q5. A teacher asks: 'A leaf is the primary site for photosynthesis. Do other green parts of the plant also perform photosynthesis?' The most accurate answer, based on the chapter, is

• A. No; only leaves perform photosynthesis because only leaves have stomata.
• B. Yes; other parts of the plant that contain chlorophyll also perform photosynthesis.
• C. No; roots also perform photosynthesis because they absorb water.
• D. Yes; all parts including non-green roots perform photosynthesis.

Q6. Consider the following items: I. Carbon dioxide. II. Oxygen. III. Water. Which of these are raw materials of photosynthesis as listed in the chapter?

• A. I and II only
• B. II and III only
• C. I and III only
• D. All three

Q7. According to the 'Know a Scientist' box on Rustom Hormusji Dastur, which of the following was NOT among the factors he studied in relation to photosynthesis?

• A. Soil colour of agricultural fields
• B. Amount of water available to plants
• C. Temperature of the surroundings
• D. Colour of light

Q8. Assertion (A): In Activity 10.6, the thin layer for microscope observation is carefully peeled from the LOWER surface of a leaf such as rhoeo or money plant. Reason (R): Stomata are generally found on the lower surface of the leaf.

• A. A is true, R is false.
• B. Both A and R are true, and R is the correct explanation of A.
• C. Both A and R are true, but R is NOT the correct explanation of A.
• D. A is false, R is true.

Q9. Consider the following statements about stomata: I. They help in the exchange of oxygen and carbon dioxide during photosynthesis. II. They help in the exchange of gases during respiration as well. III. They transport water from roots to leaves. Which statements are correct?

• A. I and III only
• B. II and III only
• C. I, II and III
• D. I and II only

Q10. In Activity 10.5, set-up A (water plant in sunlight) shows bubbles in the inverted test tube, but set-up B (water plant in the dark) shows none. The best conclusion is that

• A. Oxygen is given out by the plant only when carbon dioxide is absent
• B. Oxygen is given out by the plant only when caustic soda is present
• C. Oxygen is released only during photosynthesis, which needs sunlight
• D. Oxygen is released during respiration in the plant

Q11. In Activity 10.7, after the plant in red-coloured water has been observed, the upper part of its stem is cut and examined under a magnifying glass. Where is the red colour seen, and why?

• A. In the thin tube-like structure called xylem, because red ink moved upwards through xylem
• B. Only on the outer surface of the stem, because red ink stained it externally
• C. In the phloem, because phloem carries dissolved substances upward
• D. Only in the leaves, because leaves trap the red ink

Q12. Assertion (A): A potato slice shows the presence of starch when tested with iodine. Reason (R): The food prepared in the leaves is transported through phloem and may be stored in parts such as seeds and roots.

• A. A is false, R is true.
• B. Both A and R are true, and R is the correct explanation of A.
• C. A is true, R is false.
• D. Both A and R are true, but R is NOT the correct explanation of A.

Q13. In Activity 10.8, the lime water in the tube CONNECTED to the flask containing germinating moong seeds turns milky, while the lime water in a separate, unconnected control tube does not. The most direct conclusion is that

• A. Lime water naturally turns milky over 24 hours
• B. Carbon dioxide is naturally present in air in large quantities
• C. Cotton releases carbon dioxide when wet
• D. Germinating seeds release carbon dioxide during respiration

Q14. Question 10 of the chapter asks why photosynthesis and respiration are essential to maintain balance in nature. The best explanation is that

• A. Respiration uses oxygen and gives carbon dioxide; photosynthesis is independent of this.
• B. Both processes use oxygen, keeping the atmosphere oxygen-rich.
• C. Photosynthesis takes in carbon dioxide and gives out oxygen; respiration takes in oxygen and gives out carbon dioxide — together they balance these gases.
• D. Photosynthesis and respiration both produce only energy, balancing it across living things.

Q15. Vani sets up four potted plants with sufficient water: (a) sunlight WITH CO2, (b) sunlight WITHOUT CO2, (c) dark WITH CO2, (d) dark WITHOUT CO2. In which set-up(s) will starch be formed in the leaves?

• A. Only (a)
• B. (a) and (b) only
• C. (a) and (c) only
• D. All four