Answer: D - Lipids
Lipids provide a long term energy storage because they contain longer C-H bonds compared to the other organic molecules, making it easier for them to store larger amount of energy. Moreover, upon burning they produce twice the amount of calories compared to that of the carbohydrates.
If he studied a small sample it wouldn't be a representative sample. since he got such a large sample there is a chance most likely all organisms follow the rules of evolution.
The age group she does fit in is Infancy
Yes he can.
If he was just neutered today:
Leash walks only so he can urinate and defecate. If he runs around he risks breaking sutures/glue.
If he was neutered a few days ago:
Also leash walks only until sutures fully healed
Remember to keep the e-collar on!