Fact 1: Vesicle transport requires energy, so it is also a form of active transport.

Fact 2: Much of protein transport in a cell occurs via coated transport vesicles.

Given the two facts above, answer the question "Much of protein transport in a cell requires what?" with the following options: 
- protons
 - recycling
 - oxygen
 - energy
 - atoms
 - Nutrients
 - walls
 - Energy.


 

    energy     