Most sand dunes are created by deposition by Wind.
<span>The skeletal system also protects
internal organs and produces blood cells. Bones provide calcium that is
essential for the proper functioning of the nervous system. ... Sensory receptors in joints between bones send signals about body position to the brain. The brain regulates the position of bones by controlling muscles.</span>
To deliver amino acids to their proper site during protein synthesis.
Answer:
I think its letter d........
