Which organism living within plant cells produces a toxin that kills or inhibits insects that eat it?

• A. Endophyte
• B. Dormancy
• C. Drought
• D. Environment

Answer: (A)

Endophytes are microorganisms that live inside plant tissues, often within grasses. Some fungal endophytes produce alkaloid compounds that act as natural insecticides or deterrents, so insects that feed on the plant are killed or inhibited. This protective chemical production helps the plant tolerate herbivory. Dormancy, drought, and environment aren’t organisms and don’t produce toxins inside plant cells, so they don’t fit the description. The organism that matches—one living within plant cells and producing insect-toxic compounds—is the endophyte.