Concept:Jumbled sentences need logical ordering to form a coherent paragraph. Focus on the flow of ideas about shifts in dominant life forms and evolution.
Explanation:Sentence S1 introduces that each geological period has a dominant life form. Sentence R follows logically, explaining that within each period, natural selection creates adaptive experiments leading to breakthroughs that cross into the next period.
Sentence S then states that each breakthrough depends on previous ones, making evolution progressive.
Sentence P details that individual shifts rely on opportunity, ecological access, and new adaptation.
Sentence Q completes the sequence by noting that shifts are rapid and followed by adaptive radiation, giving the example of life on land.
This order (R, S, P, Q) connects naturally from S1 to S6, which mentions that new biological systems are rare.
Answer:The correct sequence is RSPQ, which corresponds to option C.