TOEFL Listening: ETS-TOEFL听力机经 - 736U4T3UY9XJNSJ3P$

According to the professor, what is an advantage of using plant seeds rather than plant leaves to extract proteins? A. Proteins can be extracted more quickly from seeds than from leaves. B. Proteins from seeds are more effective as medication. C. Seeds can be stored without the proteins' losing their effectiveness. D. A single seed provides more protein than a single leaf.