TASK DEFINITION: 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.
PROBLEM: Fact 1: Grasses supply most of the food consumed by people worldwide. 
Fact 2: Wheat is a grass-type plant.

SOLUTION: wheat is a plant that is consumed by people worldwide.

PROBLEM: Fact 1: wind is used for producing electricity. 
Fact 2: Differential heating of air produces wind.

SOLUTION: Differential heating of air can be harnessed for electricity production.

PROBLEM: Fact 1: Many corals secrete an exoskeleton that builds up to become a coral reef. 
Fact 2: An atoll is the third type of reef.

SOLUTION:
Atolls are built by corals secreting an exoskeleton.