Active muscles demand huge amounts of oxygen, and the circulatory system works hard to provide it. Blood carries oxygen to the muscles. When the body is at rest, blood carries nutrients to the muscles so that they can repair and rebuild themselves. Blood also carries away the waste products that hard-working muscles produce, back out through the lungs to be filtered.
so they Circulatory system xx muscular system :)
Answer: the structure of an atom: At the center of the atom, there is a very small region called the nucleus. This area makes up most of the mass of the atom.
The area around the nucleus is called the electron cloud. This area makes up the majority of the volume of the atom. The electron cloud is mostly empty space.
Explanation: Hope this helps :)
Animals that use echolocation. Bats, whales, dolphins, a few birds like the nocturnal oilbird and some swiftlets, some shrews and the similar tenrec from Madagascar are all known to echolocate.
Answer:
oh fella I have given you the answer it is A sexual (take care bye)