Which of the following is the best definition of an atom? A. A particle within the nucleus that has a neutral charge
B. The fundamental unit of all matter, both living and nonliving
C. A positively charged particle within the nucleus
D. A negatively charged particle that circles the nucleus

What is thought to have caused the mass extinction at the end of the cretaceous period?

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

In which layer do organisms on earth love?