Why do puppies have different toenail thickness even though they were born form the same parents and litter? How do is the gene result in different toenails?

He should put sand around the spill in order to contain it so that it won't spread

Molecules called lipids have long hydrocarbon chains that determine the way they act. they can be fats, oils, or hormones, and even exist in our cell membranes 

The return of the wolf to yellowstone national park will probably affect the bird population to some degree, not significantly. while wolves will hunt birds when necessary, they prefer to hunt larger prey. the bird population will most likely only be affected when hunting is scarce for the wolves. birds of prey will also probably not be affected as much as other birds who spend more time on the ground hunting for food as the tend to spend more time in the air or in trees since they do not need to stay on the ground for long due to the nature of the way they hunt.