However when under duress by pests, such as when ants destroy their roots, plants are known to produce chemicals to ward
off invaders. So for this study, Barbero and her colleagues grew oregano in enclosed terrariums with
Myrmica ants, and then collected the chemical scents emitted to produce chemicals to ward off invaders.
The researchers found that the plants made twice as much of a chemical agent
called carvacrol versus normal plants grown without Myrmica ants. Carvacrol is a known bug killer, but in a surprising
twist, the researchers found that Myrmica ants switch on a set of genes that neutralize oregano’s chemical weapon.
Use the excerpt to answer the question.
Which detail was left uncertain in the article?
a. how much carvacrol the oregano plants made
b. the definition of carvacrol
c. why ants other than Myrmicas are not resistant to carvacrol
d. why plants produce chemicals to ward off invaders