Question

review the second and third paragraphs.
for many linguists, biological factors are the most important in language learning. some argue that some linguistic knowledge must exist in our brains from birth because children cannot possibly encounter every feature of their language before the age of five. this argument, called the poverty of the stimulus, contends that children must have an innate language \device\ to make up for their limited exposure. indeed, these linguists point out that nearly all children can produce the same kinds of complex sentence structures by the age of five, even without having heard them before.
many researchers have theorized what this innate linguistic knowledge must look like. one popular theory is universal grammar. this theory posits that all languages have the same basic structural foundation. that foundation is
how do the second and third paragraphs work together?
they present a scientific debate and then discuss what all linguists agree on.
they present a specific theory and then propose a novel study to prove it.
they present a general argument and then disprove a counterargument.
they present a general argument and then explain a specific theory.

Explanation:

The second paragraph presents a general argument about biological factors and innate language "device" in language learning. The third paragraph then explains a specific theory (universal grammar) related to that general argument.

Answer:

They present a general argument and then explain a specific theory.