Oxygen is the correct answer.
Answer:
homologous structures.
Explanation:
If you look at many different organisms, you will see similar structures. Like humans have a forearm, birds have a wing, whales have fins, leopards have legs. The bones evolvolved to fit the animal
There's 18 atoms in ammonium phosphate
To covert from moles to atoms times the number of moles by Avogadro's Number (6.022×10²³)
4.0 × 6.022×10²³ = 2.4088×10^24