digest and recycle the cells used components by breaking down proteins, nucleic acids, carbohydrates.

Lysosome

A lysosome is spherical membrane-bound organelle. In the lysosome, there are many hydrolytic enzymes which role is to break down different kind of molecules and components used by the cell. The pH inside of the lysosome is low (acidic: 4.5 - 5.0) which is optimal for enzymes. Also, there are substances involved in energy metabolism, cell signalling, etc.

d.) circle motion requires a force to give it a centripetal acceleration.