The tendency of toxins to accumulate in top predators is called biological ________.magnificationmitigationconcentrationremediation

The correct term to fill in the blank is "magnification."

Explanation:

Biological magnification, also known as biomagnification, refers to the process by which the concentration of toxins, such as pesticides or heavy metals, increases in organisms at each trophic level of a food chain. When smaller organisms absorb these toxins from their environment, predators further up the food chain consume these organisms, leading to a higher concentration of the toxins in the bodies of these top predators. As a result, the top predators often have significantly higher concentrations of toxins compared to their prey, which can lead to various health issues, including reproductive failures and mortality.

In contrast, the other options do not accurately describe this phenomenon:

• "Mitigation" refers to the act of reducing the severity of something, such as pollution, rather than the accumulation of toxins.
• "Concentration" could be a general term describing the presence of toxins but does not specifically indicate the increase through trophic levels.
• "Remediation" involves the removal or reduction of pollution from an environment, thus it doesn't relate to the accumulation in food chains.

Therefore, the completed sentence reads: "The tendency of toxins to accumulate in top predators is called biological magnification."