the tails of the core histone proteins can be chemically modified by the covalent addition of what type of chemical group?

Cells destroy body cells infected by a virus or bacteria.

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

Wich is not standing in the way of astronomers getting a good view of different star