How might natural variations in humans have contributed to their ability to survive diseases
such as the Black Death?

Which kind of aquatic ecosystem does the photograph most likely show? a. marsh b. swamp c. lake d. river

An ecologist is studying the effects that a population of predators is having on a population of a prey. he used data from the field to produce this graph. which conclusion can draw from the graph?

Nucleic acid certain protein cell membranes certain carbohydrates