What uses protein channels to move materials across the membrane

Cells tend to have a relatively small and uniform size. why aren’t cells larger?

Explain how the political influence of african americans leaders became weaker.

Suppose you use three different scale to weigh a bag of oranges. one scale says the nag weighs 2.1 lb, and third says it weighs 2.1 lb. the actual weight of the bag of oranges is 2.153 lb. which of the following best decribes these results?