A farmer who spills liquid fertilizer is likely poisoned through which route?

The correct answer is absorption, as the primary concern with liquid fertilizers often relates to how they can enter the body through the skin. When a farmer spills liquid fertilizer, the skin can absorb the chemicals present in the fertilizer, potentially leading to systemic toxicity. This route of exposure is significant because many agricultural chemicals are formulated in a way that allows them to penetrate the skin, causing adverse health effects.

Inhalation is a potential route for exposure when dealing with fumes or aerosols, but a spill typically presents more immediate risk via skin contact. Ingestion, while possible if the fertilizer contaminates food or drink, is less likely during a typical spill scenario. Injection is generally not a typical route of exposure for a spilled liquid fertilizer, as this would require a specific mechanism such as a needle puncture or similar incident. Thus, absorption stands out as the most probable method of poisoning in this context.