Its a verb because biking is an action.
A verb is a word used to describe an action, state, or occurrence, and forming the main part of the predicate of a sentence, such as hear, become, happen.
Examples of Action Verbs in Sentences
- Anthony is throwing the football.
- She accepted the job offer.
- He thought about his stupid mistake in the test.
- John visited his friend for a while and then went home.
- The dog ran across the yard.
- She yelled when she hit her toe.
- The cat sat by the window.