How do dams create energy for cities nearby

According to the cladogram, which organisms have roundworms as a common ancestor?

The energy required to vaporize a certain amount of a substance is greater than the amount of energy necessary to raise the temperature of the same amout of that substance by 1 degreee celcius

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?