Fact 1: Mutations may change the structure of a chromosome or just change a single nucleotide.

Fact 2: Nucleotides are the building blocks of DNA .

Given the two facts above, answer the question "mutations may change the structure of the what of DNA?" with the following options: 
- personalities
 - mutations
 - solid, liquid, gas
 - building blocks
 - gastropod shells
 - Veins and arteries.
 - hosts
 - an organism's body


 

    building blocks     