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.

Input: Consider Input: Fact 1: eyes are used for seeing by animals by sensing light. 
Fact 2: Light waves are electromagnetic waves.

Output: eyes are used for seeing by animals by sensing electromagnetic waves.


Input: Consider Input: Fact 1: Insects generally have two pairs of wings for flight. 
Fact 2: Flight enables many insects to move quickly away from predators.

Output: insects generally have two pairs of wings to move quickly away from predators.


Input: Consider Input: Fact 1: an animal needs to attract a mate to reproduce. 
Fact 2: Sex is a complicated way for an organism to reproduce itself.


Output: an animal needs to attract a mate for sex.