Herbicides that kill some plants with little or no injury to others are called

• A. Selective
• B. Nonselective
• C. Systemic
• D. Contact

Answer: (A)

Selective herbicides target differences between plant species, allowing them to kill certain plants without harming others. They exploit variations in physiology or metabolism—pathways or enzymes that are essential in target weeds but either less essential or protected in the desirable plants. That’s why you can use a product in a lawn that kills broadleaf weeds while leaving the grass unharmed. In contrast, nonselective herbicides affect a wide range of species, and terms like systemic or contact describe how the chemical moves or acts inside a plant, not whether it distinguishes between species.