Different animals display different needs for different foods depending on their species. For example, a human will eat meat if they need protein and they will eat lemons if they need citrus. Animals are the same way. The animals will eat different foods depending on their needs and preference.
I didn't fully understand the question, but I hope I was able to help/give the right answer. :)
Environment affects animal behavior by changing the availability of survival resources like food & shelter, as well as situational things like proximity to human activity. Sometimes the same species of animal will behave completely differently in a forest environment compared to an urban environment.
The integumentary system, which includes the skin, protects the body and regulates temperature/homeostasis. It also eliminates small amounts of waste, but it does not aid in movement directly.
