Biology
Assertion (A): Stomata are tiny openings found mainly on the lower surface of the leaves.
Reason (R): They cannot be opened or closed for the process of photosynthesis when exposed to direct sunlight as guard cells become inactive in direct sunlight.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Answer
A is true but R is false.
Reason — A is true as stomata are tiny pores mainly found on the lower surface of leaves in most plants. They help in gas exchange and transpiration.
R is false as stomata can open and close. They are controlled by guard cells, which regulate opening based on conditions like light, carbon dioxide levels, and water availability. Stomata often open in sunlight to allow carbon dioxide intake for photosynthesis, not become inactive.
Therefore, A is true but R is false is the correct option.
Related Questions
Which of the following chemicals is used to identify the presence of starch ?
- Lime water
- Potassium hydroxide
- Iodine solution
- Methylated alcohol
Assertion (A): Green plants are autotrophs and they use carbon dioxide and water as raw materials to prepare their own food.
Reason (R): Chlorophyll and sunlight are also essential in the process of photosynthesis but they are not utilized as raw materials.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): The extensive network of veins within the leaf lamina supplies water and minerals in every cell and also helps in the translocation of prepared food to the other parts of the plant.
Reason (R): The flow of fluids in the veins of leaves or veins of our body, both are unidirectional.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): More energy is released (38 ATP) in the aerobic respiration as compared to anaerobic respiration during which only 2ATPs are produced by the breakdown of one molecule of glucose.
Reason (R): Complete oxidation of glucose occurs in presence of oxygen whereas glucose cannot be broken down completely in absence of oxygen. Hence, amount of energy produced varies between the two kinds of respiration.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.