Im not sure but i believe it could be C
the surface area of a figure in square units is the number of unit square it takes to cover entire surface without the gas or overlapse if three dimensional figure has + sides the sides called faces the surface area is the total of the area of the faces
Sweat glands is the major function in thermoregulation.
Photosynthesis makes a sugar for the plant, in order for photosynthesis to occur the plant needs carbon dioxide and water, and with the use of the sunlight it produces oxygen and glucose. For respiration you need glucose and oxygen which produces carbon dioxide, water and ATP(energy) for the cell. I hope this helps, I only know the first half of the question.