Where does most exogenous antigen presentation take place?

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

What have we learned from fossil evidence about evolution? a) it is an abrupt change. b)the process is observable. c) it takes place during one lifetime only. d)the most complex traits are always selected.

Coquina, a type of limestone, forms from shell fragments that settle on the ocean floor. what type of rock is coquina?