1. Sex education
2. Chaperones.
3. Parents actually taking care of kids.
4. Having a 1v1 conversation.
The answer is A (Tar).
Tar appears on lungs when somebody smokes cigarettes.
I'm 100% correct, I've learned about this for years. Hope this helps!
Babies are born with about 300 bones, almost a third of which eventually fuse together to form the 206-bone skeleton of an adult.