Answer: to explain what keystone species are important in each ecosystem
Explanation:
The overall theme of the article is to explain what keystone species are important in each ecosystem.
Keystone species is referred to as an organism that defines the ecosystem as a whole. They help define the habitat's biodiversity.
It should be noted that despite the fact that every living organisms depends on each other, some species are more vital than others and when they're removed, there will be a drastic change in the habitat.
Answer:
A Starfish is Triploblastic meaning they consist of three germ layers. Hydra are diploblastic meaning they consist of only 2 germ layers.
Because Spain held such a dominant presence in the America's, Portugal focused on Africa. The correct option among all the options given in the question is option "A". The Spanish empire back then was one of the largest empire among all the empires. They were the masters of exploring the world via sea route and so they had created colonies far before the other. In America the Spanish were already present and expanding when Portugal decided to look elsewhere for creating colonies.
The answer is D glycolysis
Regolith can be brought back to earth.