It retains salt and water within the circulation
A nebula is an interstellar cloud of "Dust and Gas"
Explanation:
Bones shape our body and help is to stand up straight. Muscles are attached to bones, they help us walk and run and smile. All the bones in our body make up our skeleton - from the top of our skill to the tips of our phalanges at the end of our toes. Muscles stretch across our bones and are attached with tendons.
B is not correct because new molecules are formed so numbers can change. D isn't correct because the color often changes, for example metallic iron and clear oxygen form red rust. The arrangement of the atoms changes, too so a isn't correct. C is cotrect
