People suffering from alzheimer's disease have much lower levels of acetylcholine in the

Asap! how does the distance between two objects affect the force of gravity? how is the moon dependent on the sun?

Which of the following is an oxidation-reduction reaction? (pictured below)

Up until 1938, paleontologists accepted the idea that coelacanths (an ancient fish) went extinct at the time that they last appear in the fossil record, about 80 million years ago. but in 1938, a live coelacanth was discovered off the coast of south africa that was compared to the fossil record and found to be the same species what goal of science does this discovery represent