Herbicides are chemicals used to

Step 1: Analyze the question The question asks what herbicides are used for. The key is the word itself.

Step 2: Explain the concept Pesticide names often come from the Latin suffix -cide, meaning "killer", and a prefix that tells you the target:

• Herbi- (herb, meaning plants) → Herbicides kill unwanted plants (weeds)
• Insecti- → Insecticides kill insects
• Fungi- → Fungicides kill fungi
• Rodenti- → Rodenticides kill rodents
• Nemati- → Nematicides kill nematodes

Examples you may know from Nigerian farms are paraquat, glyphosate (Round-up) and atrazine. Farmers spray them to kill weeds that compete with crops for water, light and nutrients.

Step 3: Evaluate the options

• A. Check the spread of diseases: This is the job of disinfectants, antibiotics, or vector control, not herbicides.
• B. Control dormancy in seeds: This relates to plant growth regulators such as gibberellins, not herbicides.
• C. Control insects: These are insecticides.
• D. Control weeds: Correct. Herbicides are weed killers.
• E. Control pests: This is too general. "Pesticide" is the broad term for chemicals that control pests, and herbicides are only one specific type that targets weeds.

Step 4: Answer The correct option is D. control weeds.

Exam tip: Look at the prefix. Herbi- means plants/weeds, insecti- means insects, fungi- means fungi. Once you link the prefix to its target, these questions become easy marks.