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:

rising temperatures because when water vapor in the air is cooled, it condenses. it turns back into a liquid and attaches to dust particles in the air. these very small water droplets group together to form clouds

the elements of art are the visual tools that the artist uses to create a composition. these are line, shape, color, value, form, texture, and space.

the principles of art and design are balance, contrast, emphasis, movement, pattern, rhythm, and unity/variety.