What has involvement in the immune system

. __C__ I am useful for a fast source of energy. 2. __P__ I have involvement in the immune system (ex: antibodies). 3. __L__ I am helpful for long term energy storage. 4. __P__ I have a large role in muscle development. 8. ___P_ Enzymes, which can speed up reactions, belong in my category. 11. __N__ My category includes genetic material. 9. __L__ I am important for insulation. 5. ___C_ If athletes "pasta load," they consume a lot of me. 7. __P__ I make up cell membranes. 6. __N__ A mutation in DNA would initially start with me. 10. ___C_ I contain elements C, H, and O and have a ring-like structure. 12. __L__ I can contain long fatty acid chains.

Scientists use sampling to get an estimate of things they can't easily count. Scientists keep track of the change (increase or decrease) of population numbers to make decisions about issues that affect that population.