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: Veins generally carry deoxygenated blood. 
Fact 2: Blood carries blood cells.

SOLUTION: Veins carry cells.

PROBLEM: Fact 1: Behaviors that improve fitness increase through natural selection. 
Fact 2: Many organism behaviors have evolved through natural selection.

SOLUTION: An organism's fitness is a result of evolution.

PROBLEM: Fact 1: if heat is conducted to an object then that object will become hot. 
Fact 2: Because the surface of the ocean is heated by sunlight, the depths are cooler.

SOLUTION:
if sunlight is conducted to the surface of the ocean then it will become hot.