Questions: Question 19 (5 points) succession involves a pioneer species. A) Quaternary B) Secondary C) Tertiary D) Primary Question 20 (5 points) Why is water called the universal solvent? A) Water can act as a solvent in

The answer is the fourth one (D): Primary succession involves a pioneer species.

Explanation for each option: A) Quaternary - Incorrect. Quaternary succession is not a commonly used term in ecological succession. B) Secondary - Incorrect. Secondary succession occurs in areas where a disturbance has happened but soil and some organisms still remain. It does not typically involve pioneer species. C) Tertiary - Incorrect. Tertiary succession is not a commonly used term in ecological succession. D) Primary - Correct. Primary succession occurs in lifeless areas where there is no soil, and pioneer species are the first to colonize these areas.

For Question 20, the answer is incomplete, so I cannot provide a full response.