It's so broad, it includes physics, chemistry and biology
It is the spinal cord. Signals reach teh spinal cord, and then are transferred to the brain.<span />
Paleontologists can identify organisms that may be ancient relatives of those living today. By looking at fossils they can also suggest how these organisms lived together in an ancient habitat. Few organisms become fossilized because the circumstances that an organism has to be in is very specific.
When a scientific experiment is carried out in a controlled setting, all variables are kept the same except for the C. experimental. Experimental variables are the things you are studying in the experiment and it is the only variable you can change.