‘Great Barrier Reef’ is the world’s largest coral reef system, located in which country? 'ग्रेट बैरियर रीफ' विश्व की सबसे बड़ी मूंगा चट्टान प्रणाली है, जो किस देश में स्थित है? , ‘Great Barrier Reef’ is the world’s largest coral reef system, located in which country?