What role do predators play in maintaining the balance of an ecosystem?

Can someone i have no idea of how to do this.

Which set of terms best describes a community of miners who live out in the countryside of west virginia and use specialized geographical equipment to analyze the composition of rocks

Asap many people try to eliminate fat from their diets which is one reason it is necessary for humans to eat fat a) fat is the only way to get energy b) every cell in the body must contain fat c)fat stores less energy than polysaccharides d) saturated fats make blood vessels healthier