Fact 1: Oxygen is essential for cellular respiration for all aerobic organisms.

Fact 2: Arteries carry oxygen to tissues and organs.

Given the two facts above, answer the question "What are essential for cellular respiration?" with the following options: 
- leaves
 - Energy
 - arteries
 - Energy.
 - branches
 - glucose
 - acetic acid
 - skull


 

   arteries      