When people living on hills put in concrete barriers, plywood fencing, and drainage pipes, they are trying

What word is used to describe differences of individual organisms

Ais a landform that is formed at the mouth of a river from the deposition of sediment carried by the river as the water flows.

Of your good in bio kusing a series of preliminary observations; pstate a problem developed from these observations, formulate a hypothesis, design an experiment to test the hypothesis