The correct answer to the question is option 1, biological magnification. Biological magnification refers to the process by which non-degradable chemicals, such as heavy metals or pesticides, become increasingly concentrated in the bodies of organisms as they move up the food chain.

This happens because these chemicals are ingested by organisms at the lower trophic levels, such as plants or small herbivores. As these organisms are consumed by predators at higher trophic levels, the chemicals are accumulated and stored in their bodies. Since these chemicals cannot be broken down or excreted, their concentration increases as they move up the trophic levels.

Option 2, chemical magnification, is not the correct term and does not accurately describe this process. Option 3, residue magnification, is also not the correct term and does not describe the accumulation of non-degradable chemicals in the food chain. Therefore, the correct answer is option 1, biological magnification.