If you want to know how long pesticides will last in soil, you should consider that they are broken down by?

• A. Bacteria and fungi.
• B. Birds and fish.
• C. Humans.
• D. Plants.

Answer: (A)

The main idea here is that the persistence of pesticides in soil is largely governed by how quickly they are broken down by soil-dwelling organisms, especially microbes. Bacteria and fungi act as the primary processors of many pesticides, using the chemical as a food or energy source and converting it into smaller, often harmless, compounds. This biodegradation is influenced by the chemical’s structure and soil conditions such as temperature, moisture, pH, organic matter, and oxygen availability. When these conditions are favorable, microbial activity can significantly shorten a pesticide’s residence time; when they’re not, the compound can linger longer.

Birds and fish don’t break down pesticides in soil, and they aren’t the drivers of soil degradation. Humans don’t contribute to soil breakdown in the field, and while some plants can take up pesticides or, in rare cases, transform some compounds, they aren’t the primary means by which pesticides are degraded in soil. So the factor that most determines how long pesticides last in soil is the activity of bacteria and fungi.