Answer:
i think frst one plz i am new so sry if i am wrong
The main responsible for the delay among the atrial and
ventricular contractions is the action potential conduction velocity of the AV
node cells. If the atria and ventricles contract simultaneously, atria cannot
give any help in filling the ventricles, which is needed, especially in those
with stiff ventricles as in the elderly. Hence atria have to contract first and
then the ventricles.
The answer is D.
The longer life expectancy
Hope this helps :)
There are tons of answers you could have.
One, for example:
Increased levels of CO2 decreases DO levels in the water and suffocates organisms, leading to population drops that can cause a genetic bottle neck effect, thus decreasing overall biodiversity. This could lead to extinction
