What is the best evidence that many different geologic periods are represented in Virginia? The presence of fossils of different ages The length of its rivers The location of the Piedmont The amount of chemical weathering

## Step 1
The question is asking for the best evidence that many different geologic periods are represented in Virginia. The options provided are: the presence of fossils of different ages, the length of its rivers, the location of the Piedmont, and the amount of chemical weathering.

## Step 2
The presence of fossils of different ages is the most direct evidence of different geologic periods. This is because fossils are remnants of organisms that lived in different geologic periods. The age of these fossils can be determined through various methods such as radiometric dating, which can provide a precise age of the fossils.

## Step 3
The length of rivers, the location of the Piedmont, and the amount of chemical weathering do not provide direct evidence of different geologic periods. These factors can be influenced by a variety of factors, including human activities, and do not necessarily reflect the geologic history of the area.