No they don't. They never cross each other because of the way that they are drawn, similarly to how height is represented. That's why they never cross.
THERE ALL GREEEN INSIDEEEEEEEEE
Answer:
Water levels and mineral salts in the blood are controlled to protect animal cells by stopping too much water from entering or leaving them. The concentration of water and salts is the same inside and outside of the cells. If body cells lose or gain too much water by osmosis, they do not function efficiently.
Answer:
after forming a hypothesis... the next step is to prove that hypothesis write or wrong by doing experiments