<span>Primary succession begins in barren areas, such as on bare rock exposed by a retreating glacier. The first inhabitants are lichens or plants—those that can survive in such an environment. Over hundreds of years these “pioneer species” convert the rock into soil that can support simple plants such as grasses. These grasses further modify the soil, which is then colonized by other types of plants. Each successive stage modifies the habitat by altering the amount of shade and the composition of the soil. The final stage of succession is a climax community, which is a very stable stage that can endure for hundreds of years.</span>
Hello!
The heart is kind of like the "base" or "hub" for blood. The heart will send of blood and receive blood, and send it off again. It allows for blood to be bumped through the whole body.
I hope this helps!
3rd and 4th awnsers are correct
Answer - The living species comprise more number of hydrogen atoms in comparison to any other atoms, still 65 percent of the usual organism's mass is oxygen. The prime reason for this is that an atom of oxygen comprises sixteen times more mass in comparison to a hydrogen atom. hopes this helps :)