Answer the following question given this paragraph: 

Cleavage is the tendency of a mineral to break along certain planes. When a mineral breaks along a plane, it makes a smooth surface. Minerals with different crystal structures will break or cleave in different ways ( Figure below ). Halite tends to form cubes with smooth surfaces. Mica tends to form sheets. Fluorite can form octahedrons.


Q: What term is used to describe the tendency of a mineral to break along certain planes?

 Choices:

- tooth decay

- porosis

- erosion

- cleavage

A:
cleavage
