Volcanic mountains,
Let me know if i'm wrong.:)
They allow the heart to pump more blood by decreasing the ESV.
The answer to this is the last option i think
Answer:
A way a disease that is fatal can stay in the population is if its hereditary. Such as, it allows the carrier to live long enough to have children, which have the chance to either get it, or pass it on to their children.
Hope this helps!
Explanation:
