That individual wouldn't be able to breed. If it happened to many the species would die out
In that case you can have no children.
The species would die out - as there would be no way to reproduce.
the earth will become extinct eventually
If the blood of the circulatory system is missing, then you have a dessicated corpse or mummy of some kind.
The reproductive system is important! In fact, without the reproductive system, species would not be able to reproduce and life would not exist!
The reproductive system. Only with regards to the individual of course!
IF there was not a male reproductive system then there would be no offspring.
You wouldn't grow you will look like a kid
Yes, in fact women and men who suffer from cancers/diseases of the uterus and male sex organs, will often have a hysterectomy or vasectomy respectively, to remove the organs. You will live, just be unable to have children of your own (especially if you have had a hysterectomy).
It would depend on which animal you are referring to, mammals have much the same reproductive system. Birds, fish and insects which are also animals do not.
Death
We would no long be able to have children and humans would die out.
Firstly, we would not be alive if there was an eco-system member missing because every one is imporant. For example, trees. If they were missing we can't live because it provides us oxygen.