Fact 1: Glucose is used for energy by the cells of most organisms.

Fact 2: Human muscle cells produce energy for contraction from glucose.

Given the two facts above, answer the question "Where do humans receive energy from?" with the following options: 
- Heat
 - The Sun
 - sunlight
 - Their brain
 - Water
 - retina
 - ovaries
 - Glucose


 

        Glucose 