Proteins have structural roles throughout the body. Carbohydrates are the major energy source for cells in the body. I am unsure if lipids or nucleic acids apply.
Neurons, act as the communicators of the nervous system. Neurons receive information, integrate it, and pass it along. They communicate with one another, with cells in the sensory organs, and with muscles and glands.
Information was taken from: http://www.sparknotes.com/psychology/psych101/thebrain/section2/
In case you would like to do further reading.
4 is B. It wasn't in the genes to get short wings.
5 is C. It should be natural selection but adaptation is another way to say ns.