You are presented with the question "What does an animal require for survival?" and the following answer choices: 
- layer of body fat under skin
 - A compound that donates proton
 - Molecular kinetic energy
 - mineral particles and organics
 - a complete digestive system
 - converting food to energy
 - keeping food fresh for long periods of time
 - Something made primarily of oxygen and nitrogen

Now knowing that an animal requires air for survival and air is primarily oxygen and nitrogen, choose the best answer.


 

        Something made primarily of oxygen and nitrogen 