I'm not sure but it might be C
Two key characteristics of a good scientific investigation are hypothesis and observation of whatever organism your studying.
-Water evaporates and condenses into clouds, then the clouds are blown over the ocean, and it rains.
-Water from a mountain flows down and into a river. The river empties into an ocean.
There are three main types of galaxies<span>: Elliptical, Spiral, and Irregular. Two of these three </span>types<span> are further divided and classified into a system that is now known the tuning fork diagram. When Hubble first created this diagram, he believed that this was an evolutionary sequence as well as a classification.</span>