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: Most pituitary hormones control other endocrine glands. 
Fact 2: An abnormal endocrine gland is often blamed for producing obesity.

SOLUTION: Pituitary hormones can be blamed for producing obesity.

PROBLEM: Fact 1: coal is used for generating heat by burning. 
Fact 2: Thus, the food is cooked by heat generated internally.

SOLUTION: coal can be used to cook food.

PROBLEM: Fact 1: Mutualism is a symbiotic relationship in which both species benefit. 
Fact 2: Symbiotic microbes live in the mussels' gills.

SOLUTION:
Mutualism is a relationship like that of microbes and mussels in which both species benefit.