According to the findings, overgrazing by purple sea urchins makes them less appealing to predators.

• A. More predators are attracted to the urchins
• B. Predators ignore the urchins entirely
• C. It increases the urchins' defenses
• D. It reduces the appeal of the urchins to many predators

Answer: (D)

Predators focus on prey that offer the most energy with the least effort and risk. When purple sea urchins overgraze, something about their condition makes them a less rewarding meal to many predators. As a result, predators are less likely to target them, which matches the finding that the urchins’ appeal to many predators is reduced. This directly reflects the observed change in predator behavior.