Which structure of the excretory system in humans is responsible for cinverting ammonia into urea

An ecologist studied the same species of deer during the summer and the winter. she noticed that during the summer, when there was plenty of food, the deer were energetic and playful. however, during winter when food was scarce, the deer moved more slowly and did not run unless they needed to escape a predator. which scientific fact is best supported by her observations?

How dose plate tectonics effect climate

What can happen to an enzyme as tempature rises