Question

A stomata closes when : (i) it needs carbon dioxide for photosynthesis. (ii) it does not need carbon dioxide for photosynthesis. (iii) water flows out of the guard cells. (iv) water flows into the guard cells. The correct reason(s) in this process is/are :

Why is respiratory pigment needed in multicellular organisms with large body size ?

Give reasons for the following :

The maintenance functions of all living organisms must go on even when they are not doing anything particular. Even when we are just sitting in a class or even asleep, this maintenance job has to go on. These maintenance processes require energy to prevent damage and break-down of cells and tissues, which is obtained by the individual organism from the food prepared by the autotrophs, called producers.

In the experimental set-up shown above in diagram (I) atmospheric air is being passed into lime water with a syringe while in diagram (II) air is being exhaled into lime water. The time taken for the lime water to turn milky in both the test tubes is different. Give reason.