What is the simpelest level if organization in a human being?

Scientists discover two populations of mice on either side of a major river. the two populations have almost identical genes but the mice from one side cannot breed with mice from the other. this is most likely because

If there are 350 trout found in 200 square feet of a pond measuring 1000 square feet what is the estimated trout population of the pond? a. 1350 b. 1550 c. 1750 d. 2000

Which label correctly identifies what x represents in the concept map?