Herbicides are agricultural chemicals that

Step 1: Analyze the question The question asks what herbicides do. The key is the word itself.

Step 2: Explain the concept The suffix -cide means "killer" (as in insecticide, pesticide, fungicide). The prefix herb- refers to herbaceous plants, or weeds. So a herbicide is a chemical that kills or controls unwanted plants (weeds).

Common examples used by Nigerian farmers are Paraquat, Glyphosate (Round-up), and Atrazine.

Step 3: Evaluate the options

• A. Encourage growth of weeds: Wrong. This is the opposite of what herbicides do.
• B. Increase soil fertility: Wrong. That is the job of fertilizers, manure, and compost.
• C. Improve disease resistance of crops: Wrong. Fungicides, bactericides, and resistant crop varieties help here.
• D. Suppress crop growth: Wrong. Herbicides are meant to protect crops from weed competition, not harm them. (Selective herbicides target weeds and leave the crop unharmed.)
• E. Suppress weed growth: Correct. Herbicides kill weeds or stop them from growing, so crops get more water, light, and nutrients.

Step 4: Answer The correct option is E. suppress weed growth.

Tip: Link each "-cide" to its target:

• Herbicide → Herbs/weeds
• Insecticide → Insects
• Fungicide → Fungi
• Nematicide → Nematodes
• Rodenticide → Rodents

Once you spot the target in the word, you can answer the question quickly.