Question

1. during 2016-2017 how many kilometers of the great barrier reef were bleached, resulting in destroying the whole community? edit:

Explanation:

To answer this, we refer to scientific data: In the 2016 - 2017 bleaching event, about 2300 kilometers (or more precisely, around 2200 - 2400 km range, with some sources stating approximately 2300 km) of the Great Barrier Reef experienced severe bleaching that impacted the coral communities. This is based on research and reports from marine biology and environmental science studies on coral bleaching events.

Answer:

During the 2016 - 2017 coral bleaching event, approximately 2300 kilometers (a range of around 2200 - 2400 km is also reported by different sources) of the Great Barrier Reef were bleached, severely affecting the coral community.