Is there anything else that goes with this question? I’m not sure how to answer.
An ectotherm gets its heat from external sources
(Remember "ecto" means outer, "endo" means inner)
Answer - B. Kidney function is controlled by the blood's composition and hormones.
Reasoning - Well to start off the kidneys (main) purpose function is to clean your blood which is very Important with blood composition. Second It can also and will excrete it through urine which is pretty much what it does. Oh and also a little bit of hormones.