to deliver messages to the brain to generate movement of muscles to provide a physical barrier to the body to produce carbohydrates for energy
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: What is the primary function of skin cells?
Possibilities:
- to deliver messages to the brain
- to generate movement of muscles
- to provide a physical barrier to the body
- to produce carbohydrates for energy

to provide a physical barrier to the body