What is the source of the energy converted by producers?

Suppose you are estimating the size of a blue crab population. what is the population size if the number marked in the first catch is 40, the total number in the second catch is 200, and the number marked in the second catch is 50?

In which of the following relationships is one organism always benefited while the other organism is always harmed

The human body needs energy in order to carry out life processes such as breathing. where does the body get this energy? a. from eating food b. from learning about new things c. from lying in the sun d. from sleeping