What percentage of the entire reef did the scientist sample

As a result, over 50 percent of the world's coral reefs have died in the last 30 years and up to 90 percent may die within the next century—very few pristine coral reefs still exist.

Explanation:

air enters through the nose, moves through the nasal cavity, the pharynx, the larynx, enters the trachea, moves through the bronchi andbronchioles till the alveoli.

answer; nociceptive pain;