Concept:Find the logical sequence of sentences connecting S1 to S6.
Explanation:S1 says humans lived by hunting and gathering for millions of years.
The next sentence must introduce a change from this lifestyle.
Only R begins with "Then" and describes domestication of plants and animals.
So, R is the first sentence after S1.
P follows R because "This" refers to domestication, leading to farming.
S comes next as a comment that this shift was a major turning point.
Q explains that "This change" (the shift) happened because the ice age ended, creating warmer conditions.
S6 then states that as a result (of the warmer climate), grasses grew.
Thus, the correct order is R, P, S, Q.
Answer:The correct sequence is RPSQ, which corresponds to option D.