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 !!
Well theory isnt proven. It means you have a strong idea about the subject your talking about. So if a scientist finds evidence that suggests something against the theory then it can be changed.
An increase in insulating atmospheric gasses (e.g. carbon dioxide)
Toxins are microbial proteins with a strong specificity for a target cell that exert extremely powerful and toxic effects on that cell.
<h3>What are toxins?</h3>
Toxins are molecules that are produced by certain organisms which are deadly to other organisms when these organisms come in contact with them.
Toxins are produces mostly by microorganisms as well as some plants and animals such as fishes.
Toxins are mostly proteins products are usually specific for their targets cells.
Therefore, microbial proteins with a strong specificity for a target cell that exert extremely powerful, and sometimes deadly, effects on that cell are called toxins.
Learn more about toxins at: brainly.com/question/1235358