A secondary plant compound might be used for which of

the following?

a. a new crop variety

b. a new drug

c. a soil nutrient

d. a pest of a crop pest

The given problem enquires about the primary uses of secondary compounds formed by the plants.

Many secondary derivatives/compounds play important responsive roles in herbivory and microbial infection resistance, as attractants (pigments or scents) for pollinators and seed-dispersing organisms, and as biotic and abiotic agents.

Widely, secondary compounds are used to curate new and efficient drugs.

A new crop variety- New crop variety production requires advanced technologies for producing a different strain of species.

A soil nutrient- A soil nutrient can be obtained as a plant by-product sometimes but it does fall in the category of primary uses.

A pest of a crop pest- A pest of a crop pest cannot be produced by secondary compounds of a plant.