Question

the great barrier reef in australia is facing a serious threat from coral bleaching, a phenomenon in which corals lose their colorful symbiotic algae due to increasing seawater temperatures. coral bleaching can make the corals more susceptible to disease and death, leading to a reduction in the biodiversity and resilience of the reef. scientists say that reducing local sources of pollution, such as runoff from farms and sewage, could help improve water quality and lower the stress on the corals. according to the text, what is the main cause of coral bleaching? choose 1 answer: a pollution from local farms and sewage systems b rising seawater temperatures c a reduction in reef biodiversity d growing symbiotic algae populations

Explanation:

Pour déterminer la cause principale du blanchiment corallien, on analyse le texte : "a phenomenon in which corals lose their colorful symbiotic algae due to increasing seawater temperatures".

• Option A : La pollution locale est une solution pour améliorer la situation, pas la cause du blanchiment.
• Option B : Le texte indique clairement que le blanchiment est dû à la hausse de la température de l'eau de mer.
• Option C : La réduction de la biodiversité est une conséquence du blanchiment, non sa cause.
• Option D : Le texte dit que les coraux perdent leurs algues symbiotiques, pas que leur population augmente.

Answer:

B. Rising seawater temperatures