→ Summarize the most important information, ideas, facts, etc.
presented in this article.

your answer is "the 1950's"

i believe your answer would be c.. : )

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.