How do human activities contribute to coral bleaching?

The correct choice highlights how human activities, specifically through the increase in ocean temperatures and pollution, significantly contribute to coral bleaching. Coral reefs are highly sensitive to water temperature changes; even a slight increase can stress corals and lead to bleaching. Elevated temperatures can cause corals to expel the symbiotic algae (zooxanthellae) that live in their tissues. These algae are critical for the corals' energy and color, and their loss results in the stark white appearance typical of bleached corals.

Additionally, pollution from agricultural runoff, plastics, and wastewater can further stress coral systems. Nutrient overload from these pollutants can lead to algal blooms that suffocate corals and block sunlight, which they rely on for photosynthesis.

Other options do not accurately account for the processes involved in coral bleaching. While providing more nutrients to the water may seem beneficial at a glance, it often leads to algal overgrowth, which can be detrimental to coral health. Enhancing coral growth through overpopulation and removing predators are more complex interactions that do not directly relate to the mechanisms of bleaching as caused by temperature increase and pollution. Therefore, the combination of rising temperatures due to climate change and pollution is the critical factor leading to the widespread phenomenon of coral