I think it is the 3rd one because health problems at older age.
the brain stem controls involuntary actions such as breathing, heart beating and blinking.
A high biodiversity tally may indicate that some of its organisms may be able to survive drastic environmental changes. If there weren't at least a few organisms that contribute to biodiversity, most of the biotic Earth would be gone by now.
For example, woolly mammoths were unable to adapt to the up-and-coming warmth of the poles. Because they lacked biodiversity among their species, all of them died out and weren't able to adapt to the heat.
I hope I helped!
If the Earth were a disk with its surface perpendicular to the rays of sunlight, each point on it would receive the same amount of radiation. <span> However, the Earth is a sphere and aside from the part closest to the sun, where the rays of sunlight are perpendicular to the ground, its surface tilts with respect to the incoming rays of energy with the regions furthest away. Hope this answers the question.</span>
