Question

a bike is a system. which of the following is a part of this system?
the ground
the person riding the bike
the sounds it makes
the chain

Explanation:

To determine a part of the bike system, we analyze each option: The ground is the environment, not a bike component. The person riding is an external user, not part of the bike. The sounds are an output, not a physical part. The chain is a physical component that helps the bike function, so it is part of the bike system.

Answer:

The chain