<span>A
big variety of organisms’ genomes have genes that control the organisms’ development
at different stages. The remains of ancestral traits usually appear at
different stages of the embryological development. For example, hair growth and
loss, the development and deformation of the yolk sac or appearance and
disappearance of gill structures in the embryo development of vertebrates.</span>
Answer:
The cellular level of an organism is where the metabolic processes occur that keep the organism alive.
Explanation:
They're the only vein that carries oygenated blood
