A stem cell is a cell that has layers of bacteria that helps protect the water that follows through it.
The answer is a cellular membrane
D. an arctic fox is brown in summer and white in winter
I dont want to mislead you, but I believe the answer is A because letter B is wrong because plants go through cellular respiration and photosynthesis, whereas animals go through cellular respiration but not photosynthesis, and for C, I've never heard of that so it doesnt seem likely.
