Under certain conditions, these types of cells may be able to replace embryonic stem cells.

What is the next step in muscle contraction after the actin changes shape? (apex)

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Food webs - transferring energy and matter from one level to another. here you see four food webs. one or more are incorrect. which food web(s) show the correct sequence of organisms, from start to top level consumer? a) a b) d c) c d) a and d