Question

corals are made up of many tiny animals called polyps. most polyps are less than one centimeter across. they are related to sea anemones and have stinging tentacles.
thousands of polyps live together in groups. each coral polyp has a hard skeleton. the skeletons of all the polyps in a group form a corals structure.
a coral grows as more polyps add their skeletons. but because polyps are so small, this growth is very slow. a coral may take a whole year to grow just a few centimeters!
which of the following are characteristics of corals? select all that apply.
they grow slowly over time.
they are made up of multiple organisms.
they are all less than one centimeter across.

Explanation:

• "A coral grows as more polyps add their skeletons. But because polyps are so small, this growth is very slow" shows they grow slowly.
• "Corals are made up of many tiny animals called polyps" and "Thousands of polyps live together in groups" show they are made of multiple organisms.
• "Most polyps are less than one centimeter across" not "all corals", so this option is wrong.

Answer:

They grow slowly over time.
They are made up of multiple organisms.