Combine the given two facts to write a concluding fact. Note that there should be some parts of the first and second facts that are not mentioned in this conclusion fact. Your combined fact should be the result of a chain between the two facts. Chains form when two facts connect together to produce a concluding fact. An example of a chain is: "pesticides cause pollution" (fact1) + "pollution can harm animals" (fact2) → "pesticides can harm animals" (conclusion fact). Parts of the concluding fact overlap with the first and the second fact. To construct such a  concluding fact, a useful way is to borrow the subject from one fact and the ending conclusions from another fact.

Fact 1: All cnidarians are aquatic. 
Fact 2: Cnidarian tentacles serve to capture prey.
All aquatic tentacles serve to capture prey.

Fact 1: irradiating food can be used to kill existing microorganisms in the food. 
Fact 2: Food irradiation is blazingly high-tech.
a blazingly high-tech method can be used to kill existing microorganisms in the food.

Fact 1: the volume of an object can be used to describe the size of that object. 
Fact 2: Volume is the amount of space an object contains.

the amount of space an object contains can be used to describe the size of that object.