Answer:
This process would be the one truly responsible for the "evolution" of mitochondria and chloroplasts as we know them from their prokaryotic ancestors. The cell process that would have initiated endosymbiosis is endocytosis; the process of taking things inside the cell
Irritation Threshold is defined as the name applies. It is the threshold or maximum point at which an individual has become irritated or annoyed.
I agree with the person above - reproductive cells or sex cells are called gametes.
When it comes to women, these gametes are called an ovum, or an egg, and when it comes to men, gametes are called sperm.