Identify two examples of the benefits of having the participants keep track of their daily eating habits through this study

Ineed to know why d is the correct answer asap

Which type of bond forms between water moleculesstrong bondhydrogen bondcovalent bondpolar bond

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?