Can someone explain to me in depth the difference between covalence and ionic bonds

Discuss the functions of epithelial connective nerviud and muscular tissues

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

What environmental cues and landmarks do the geese use to determine the timing and direction of their migration over the mountains? how do they find their way?