Nina is writing an essay about conservation. Read the following excerpt from her draft below.

The Earth has a limited supply of natural resources. Some resources—such as trees—can be replaced, but some—such as coal—cannot. To make these resources last longer, people do things like walking instead of driving and using less electricity.

How can Nina improve this paragraph?

A.
by adopting a more formal style
B.
by adding facts and examples to support her ideas
C.
by using more exact words and subject-area vocabulary
D.
by adding transitions to show the connections between ideas