Atoms in a molecule are joined together by a special link called a:
a. physical action
b. chemical bond
c. formula bond
d. dynamic structure

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.