No, that answer was kind of dumb. I would have to say amino acid.
Answer:
if ur asking which one of those answer choices is the right one, it's D! Deliver oxygen to every blood cell <3
Explanation:
This involves transport of oxygen from the lung to the tissues by means of the circulation of blood.
A little trick i learnt: The atomic number reflects how many electrons there are, and there must be an equal charge. therefore, there are the same amount of protons as there are electrons. so if it has 81 protons, we look for number 81 in the periodic table, Thallium
I think the answer is 1, change ammonia into nitrates.