In what kind of animal material do toxins like mercury concentrate?

Can you please help me.

What do scientists need to look at before developing an argument

Mrna decodes information from the original dna master plan to build proteins in the during the process of ribosomes.

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons