DISCUSSION: Primary substances are only mentioned in part of the first paragraph. They’re mentioned to provide contrast with secondary substances. This information clarified what secondary substances are and are not.
- We’re told that primary substances are required for plant growth (line 7), but we’re not told how they help growth.
- CORRECT. By mentioning primary substances, the passage clarified what secondary substances are not.
- No. The distinction is between selecting characteristics that help pollination, and selecting characteristics that defend against predators. That’s all done with secondary substances. We’re not told whether insects have a role in selecting primary characteristics.
- The secondary substances have ‘a multitudinous array of chemical’ (line 9). We have no idea which chemicals are in primary substances. Maybe it’s just a few.
- Plants use secondary substances to adapt, not primary substances. See paragraph 2.
Need help with RC? → Try the RC Mastery Seminar
Solve hard passages quickly