And he is 10000 years old so he know
Both animal and plant cells undergo respiration. Although this respiration goes toward different activities (photosynthesis for plants and muscular respiration for animals), both processes intake oxygen and get rid of carbon dioxide as a waste product.
The mix of salt and fresh water forms a brackish water environment.
Would this be speciation?
A vein. This is because veins carry deoxygenated blood back to the heart.
