<span>Carbon is most abundant in the atmosphere and hydrosphere.</span>
The answer is D. The Protista have very little in common with each other besides being unicellular and Eukaryota.
Protista is one of kingdom that consist of any eukaryotic that could not classified as plant, animal or fungi. Since the classification itself based on exclusion, protist group has much less similarity than other group. All protist is unicellular and eukaryote but other than that, they will have many difference in other aspect.
All ecosystems have a feeding hierarchy
