Answer:
Option A, oxygen in the atmosphere
Explanation:
The highest level of oxygen reached during this phase of the geological cycle of earth. The oxygen level in Carboniferous period accounted for 35% as compared to 21% of oxygen in the atmosphere in present time.
Due to high oxygen content, the giant and wide varieties of terrestrial animal and plant species evolved. For example – size of insects and carwlies increased, plant became extremely giant, increase in number of tree ferns etc.
A living organism that typically grows in a permanent spot, absorbing water and inorganic substances through its roots.
As you move down a group, atomic radius increases
Answer:
multicellular
Explanation:
Animal cells do not have cell walls, which distinguishes them from other...