Differentiate between Heliophytes and Sciophytes.

Consider the following statements $(A - D)$ each with one or two blanks.
$(A)$ Some snails go into $ . . . . . . (i) . . . . . . $ to avoid $ . . . . . . (ii) . . . . . . $ related problems.
$(B)$ Since small animals have a $ . . . . . . (iii) . . . . . . $ surface area relative to their volume,they tend to lose body heat $ . . . . . . (iv) . . . . . . $ when it is cold outside.
$(C)$ Next to temperature,$ . . . . . . (v) . . . . . . $ is the most ecologically important environmental factor.
$(D)$ Every $ . . . . . . (vi) . . . . . . $ the famous Keoladeo National Park in Rajasthan hosts thousands of migrating birds.
Which one of the following options gives the correct fill-ups for the respective blank numbers from $(i)$ to $(vi)$ in the statements?

Temperature changes in the environment affect the body temperature of animals which are:

Mangroves are

The organisms that are present in tropical regions are called:

The photic or euphotic zone extends to what depth from the upper surface of the sea?