<span>geographic isolation.....</span>
The right answer is vein (it contains blood and has valves).
The infra-cardiac veins of small and medium caliber possess this system of fight against gravity. The valves consist of a dense connective tissue, surmounted by endothelial cells, corresponding to a fold of the intima. They allow blood circulation in the sense organ / heart but prevent venous reflux.
Biological structures like DNA, proteins and cells all depend on molecules. ... Neurotransmitters like epinephrine are pretty simple molecules, but without them our nervous system couldn't work. Oxygen, containing just two oxygen atoms, is a very simple molecule, and it is certainly essential to living things.
Answer:
If it´s not A then choose C
Explanation
If they were land animal and could not swim then the only logical reasoning would be that the two pieces of land drifted apart from each other and the fossils were in between them and that´s why they ended up in the ocean.
Consumers. Obviously all animals are not b or c as there are animals that are both. Plants are producers as they produce energy, and animals consume the energy making them consumers.
