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: Secondary growth forms secondary vascular tissues and bark. 
Fact 2: Trees have the ability to undergo secondary growth and produce a woody body.

SOLUTION: trees form secondary vascular tissues and bark.

PROBLEM: Fact 1: the gravitational pull of the Moon on Earth 's oceans causes the tides. 
Fact 2: Tides create current.

SOLUTION: The gravitational pull of the Moon on Earth's ocean contributes to ocean currents.

PROBLEM: Fact 1: weathering means breaking down rocks from larger whole into smaller pieces by weather. 
Fact 2: Through weathering, the surface was eroded away, exposing igneous rock.

SOLUTION:
Eroding means breaking down rocks from larger whole into smaller pieces of rocks.