When SA Node triggers Atria goes into Systole !! and when the signal reaches to AV node and from there it goes to Bundle of His making Ventricle to systole or constrict !!
So your answer is Systole !!
For mutations to affect an organism's descendants, they must: 1) occur in cells that produce the next generation, and 2) affect the hereditary material. Ultimately, the interplay between inherited mutations and environmental pressures generates diversity among species.
Humans Come From A Guy Sperm It Goes Into The Females Egg
It is true that cells spend most of their time dividing. In fact, they spend 78% of their "life" in interphase.
