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: a ship is used for moving people across bodies of water. 
Fact 2: Commonly, a bridge is a structure built to cross a body of water.

SOLUTION: For short distances, bridges can replace ships.

PROBLEM: Fact 1: Sponges have specialized cells called collar cells. 
Fact 2: Collar cells are the work horses of the sponge.

SOLUTION: Sponges have specialized cells that are work horses.

PROBLEM: Fact 1: Freshwater biomes have water that contains little or no salt. 
Fact 2: Another name for salt is sodium.

SOLUTION:
Freshwater biomes have water that contains little or not sodium.