Kindly answer these two questions. Thanks

Solution:

Ans 7. Option C) is correct: P700

Reaction centre is a term used  for a complex of several proteins, pigments and other co-factors assembled together to execute the primary energy conversion reactions of photosynthesis. Here, primary electron transfer takes place.  Reaction centre has a single chlorophyll a molecule. It  also collects light from  light harvesting complexes also. The reaction centre is different in both the photosystems. In PS I the reaction centre chlorophyll a has an absorption peak at 700 nm, hence is called P700, while in PS II it has absorption maxima at 680 nm, and is called P680.

Ans 8. Option A) is correct: The root dies first. 

If you remove the phloem from a twig, then the food will not be able to get translocated to different parts of the plant. In such a plant, the roots will die first. This is because the roots cannot synthesise their own food; thus, if the supply of food is cut down to the root, they will die. When the roots will die, the plant would not absorb water; thereby, leading to the wilting of leaves.