Answer:
mountains and rivers because a geographical barrier can be a mountains range, a large canyon, a body of water
Inner planets have thicker atmospheres.
Answer:
some kind of rope that is thick and durable
Explanation:
rope can be used in any situation and can be made sturdy, not to mention it is quite long as well.
The study of how living things are classified is called dichotomous key
Your answer !flow directly from the atrium into the ventricle