Read the following passage and answer the question by choosing among the four alternatives given:
The Great Barrier Reef is not only visually stunning but also incredibly diverse. It is home to a vast array of marine life, including more than 1,500 species of fish, 600 species of coral, and numerous other animals such as turtles, dolphins, and sharks. The vibrant colors of the coral and the teeming schools of fish create a truly mesmerizing underwater spectacle. This magnificent ecosystem serves as an important breeding ground and nursery for many marine species. It provides shelter, food, and protection for countless organisms, making it a crucial part of the ocean's delicate balance. In addition to its ecological significance, the Great Barrier Reef is also a popular destination for tourists, who come from all over the world to witness its beauty firsthand. Unfortunately, this natural wonder is facing numerous challenges. Climate change, pollution, and over-fishing are some of the major threats to the reef's health. Rising sea temperatures have led to coral bleaching, causing significant damage to the delicate coral structures. Efforts are being made to mitigate these impacts and protect the reef, including the establishment of marine protected areas and the promotion of sustainable fishing practices. Preserving the Great Barrier Reef is not only essential for the future of this unique ecosystem but also for the well-being of our planet as a whole. It serves as a stark reminder of the importance of conservation and the need to protect our natural heritage. By taking action to address the threats it faces, we can ensure that future generations will be able to enjoy and appreciate this awe-inspiring wonder of nature.
What is the main purpose of establishing marine protected areas and promoting sustainable fishing practices for the Great Barrier Reef?