If you were a scientist studying how the building of dams by a beaver population in a forest affected river water flow, soil nutrient content, and the dynamics of other populations that rely on the river water, such as fish and amphibians, you would be a specialist at what level of biology?

The scientist would be an ecologist i.e. an expert in ecology.

Explanation:

The scenario in question investigates the affect of a biotic factor (beaver population) on various abiotic factors such as water flow and soil nutrient content.

In this context, ecology is the scientific study of interactions between biotic and abiotic components of an ecosystem.

explanation:

the universal gravitation equation. since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. if the mass of one of the objects is doubled, then the force of gravity between them is doubled.

it should be d) transitional fossils.

they show the gradualism of evolution throughout a period of time