A systemic pesticide works by

A systemic pesticide works by

• A. Absorbed into organism.
• B. Must touch pest.
• C. Killed by sunlight.
• D. Being absorbed and circulated within the plant or animal.

Answer: (D)

Systemic pesticides rely on moving through the organism after uptake. They are absorbed and then circulated within the plant or animal, so the chemical travels to many tissues. In plants, this means roots or leaves take up the pesticide and it moves through the vascular system to leaves, stems, and roots, exposing sap- and tissue-feeding insects that bite or ingest those parts. In animals, the pesticide is absorbed into the bloodstream and distributed to various tissues, so parasites or pests feeding on the host ingest or come into contact with the chemical as it circulates. This internal distribution is what makes the pesticide effective even if it isn’t applied directly to every pest. Choices that describe only contact action, or reliance on sunlight, don’t capture this internal movement. Absorption alone doesn’t guarantee spread throughout the organism, and contact-only or phototoxic mechanisms don’t reflect how systemic products provide protection.

Systemic pesticides rely on moving through the organism after uptake. They are absorbed and then circulated within the plant or animal, so the chemical travels to many tissues. In plants, this means roots or leaves take up the pesticide and it moves through the vascular system to leaves, stems, and roots, exposing sap- and tissue-feeding insects that bite or ingest those parts. In animals, the pesticide is absorbed into the bloodstream and distributed to various tissues, so parasites or pests feeding on the host ingest or come into contact with the chemical as it circulates. This internal distribution is what makes the pesticide effective even if it isn’t applied directly to every pest.

Choices that describe only contact action, or reliance on sunlight, don’t capture this internal movement. Absorption alone doesn’t guarantee spread throughout the organism, and contact-only or phototoxic mechanisms don’t reflect how systemic products provide protection.