Here's why:

* Physical features are tangible, visible aspects of the Earth's surface. Fields are areas of land, typically open and flat, which are visible and can be touched.

* Human features are things created or modified by humans. While fields are often used by humans for agriculture, they are not created by humans themselves. The land exists naturally, and humans transform it for their purposes.

Therefore, a field is a physical feature that can be manipulated and used by humans.