Answer:
Water!
Explanation: It carries nutrients to cells and removes waste products. Water is apart of every tissue and cell in your body.
You didn't really provide us with any options? It must be noted that generally, the structure of the skeletal system also dictates its function. With that I mean that having bones and a skeletal system enables us to move more efficiently and to have the pose which we have.
The second trimester is when the respiratory system is mature.
Won’t pull muscles and can gain arm strength
Hope this was helpful sorry if it wasnt