I believe a <span>Stratovolcano</span>
The answer to the question is, <span>Principle of uniformity
The principle of uniformity, otherwise known as </span>Uniformitarianism, is a doctrine or principle in geology which posits that <span>the geologic processes of the Earth acted in the same manner and that these natural processes occur with essentially the same intensity in the past as they do in the present. According to this principle, such </span>uniformity<span> is sufficient to account for all geologic change.</span>
Air mass, letter a is the correct one
