Answer:
IV: Student grade level (6th, 7th, 8th)
DV: "Loudness" (Operationalizing this variable would be beneficial, or in other words, define a way to measure it)
Explanation:
I think the answer is B. Immigration must outpace emigration. Hope this helps!
From 1830 to 1833 Charles' multi-volume Principles of Geology was published. The work's subtitle was "An attempt to explain the former changes of the Earth's surface by reference to causes now in operation", and this explains Lyell's impact on science. (known for Uniformitarianism) (influenced by Charles Darwin) :)
