Actually girls grow more than boys because girls develope faster and mature faster.
Answer:
a bit like a band or ring under the microscope
A organ donation help people in his community becasue if there is a kid or even a adult he can help them by give them a new hole life, like blood of other part of the body
The brown stuff is called plaque. This forms on your teeth when you eat and its something you can't get rid of. There is tooth paste that can help maintain it.
So then scientists will have more pressure to find a cure or vaccinate them