It's the form of a verb used non-finitely, with or without the particle "to". To walk is an infinitive.
Answer:
Weathering is the breaking down or dissolving of rocks and minerals on Earths surface. Once a rock has been broken down, a process called erosion transports the bits of rock and minerals away. Water, acids, salt, plants, animals, and changes in temperature are all agents of weathering and erosion
Explanation:
Uncle Tyrones snores and the chainsaw