Lactic acid buildup when you’re exercising causes a build up of oxygen. Your body cannot break down glucose in the blood. So, your heart beat increases because there is more oxygen than normal needing to be pumped throughout the body.
In short terms: because your heart needs to pump more oxygen, it is pumping faster causing a faster heart rate.
<u>Answer:</u>
<em>It is not true to say that common ancestors occurs only within a single species rather two species with similar traits might have a common ancestor. </em>
<u>Explanation:</u>
If the ancestor is same for both the species then it is said that both the species are closely related and share common ancestor with similar evolutionary relationship.
Phylogenetic tree are drawn and studies are done to understand the ancestor of a species. The evolution has occurred from the ancestor to the new species formed.
Prophase 1, where crossing over occurs and DNA is already replicated