Ceratium fusus is a protist that is found primarily in coastal waters, especially around the coast of the united kingdom. these organisms are unique because they can undergo a special chemical reaction at night that defend them against predators. it provides defense by attracting larger predators that prey on the organisms that eat ceratium fusus. which characteristic of ceratium fusus is being described?

A chemical defense mechanism called bioluminescence .

Explanation:

As mentioned in the reaction, Ceratium fusus undergo a special chemical reaction at night that helps defend them against predators. During this reaction light is produced within a living organisms. However, this type of reaction does not produce any heat although it produce light.

What is the purpose of bioluminescence ?

The most widely known purpose of  bioluminescence is to defend the organism against the attack of predators. This is because the light confuses or startles the predators. Along with confusing the predator, the light can also alert bigger predators to come on the location of organism, this way that bigger predator will eat the predator which is threatening the organism which in our question is Ceratium fusus .

Many marine organisms use the phenomenon of bioluminescence for their defense including marine invertebrates,vertebratesm, some microorganisms as well as some fish and fungi.

Hope it help!