You are presented with the question "Some strange life forms have an envelope of what?" and the following answer choices: 
- Chemical energy
 - biological diversity
 - Something coming from a gland
 - layers of fat
 - characteristics
 - phospholipids and proteins
 - Positive charges
 - visible energy

Now knowing that some viruses have an envelope of phospholipids and proteins and viruses are strange life forms, choose the best answer.


 

      phospholipids and proteins   