Answer:
If there wasn't a lot of organisms and energy in the productive part of the triangle, then there wouldn't be a lot of third level organisms. The energy piramid would be a lot smaller then what it is here, and maybe if the energy source was low then there might not be such a vast varity of animals in the ecosystem.
You're welcome friend <3
Answer:
I'm more then sure it is A but let my know it im wrong if i am sorry :)
Explanation:
I would say zygote ® fetus ® embryo ® blastocyst
If i'm not mistaken, it's the aorta