Answer:
Temperatures gradient
Explanation:
There are distinct temperature gradient differences in the layers of atmosphere usually due to the main air molecule composition of the layers, the density of the molecules. The Troposphere the lowest layers is the densest and temperature decreases with increase in altitude. The stratosphere, on the other hand, has an increase in temperature with increase in altitude. Temperatures decrease with altitude in the mesosphere while the parameter increases with altitude in the thermosphere.
IT'S D becuse none of the other awser choses make sense so ya
. I think that bivalves have evolved to have smaller head regions because they have also evolved to have bigger shells or valves than cephalopod
It makes their blood sugar stay leveled
