Fact 1: Some viruses have an envelope of phospholipids and proteins.

Fact 2: Viruses are strange life forms.

Given the two facts above, answer the question "Some strange life forms have an envelope of what?" with the following options: 
- Chemical energy
 - biological diversity
 - Something coming from a gland
 - layers of fat
 - characteristics
 - phospholipids and proteins
 - Positive charges
 - visible energy


 

      phospholipids and proteins   