Which statement best describes systemic herbicides?

Which statement best describes systemic herbicides?

• A. It is absorbed primarily through the roots.
• B. It acts only on contact with foliage.
• C. It remains largely inactive in the plant.
• D. It is absorbed and moved within the plant.

Answer: (D)

Systemic herbicides are absorbed by the plant and moved through its vascular system to reach distant tissues. This translocation lets the chemical travel to roots, buds, and new growth, so the entire plant is affected even if only part was treated. That internal movement is what makes them effective against perennial weeds and plants with extensive root systems. In contrast, a contact herbicide acts only on tissues it touches and doesn’t move around the plant, and suggesting the chemical remains largely inactive contradicts how systemic herbicides operate. Some are taken up through leaves and move via the xylem or phloem to active growth sites, which is why the description of being absorbed and moved within the plant best captures the idea.

Systemic herbicides are absorbed by the plant and moved through its vascular system to reach distant tissues. This translocation lets the chemical travel to roots, buds, and new growth, so the entire plant is affected even if only part was treated. That internal movement is what makes them effective against perennial weeds and plants with extensive root systems. In contrast, a contact herbicide acts only on tissues it touches and doesn’t move around the plant, and suggesting the chemical remains largely inactive contradicts how systemic herbicides operate. Some are taken up through leaves and move via the xylem or phloem to active growth sites, which is why the description of being absorbed and moved within the plant best captures the idea.