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.

Ex Input:
Fact 1: Mutations that lead to cancer usually occur in genes that control the cell cycle. 
Fact 2: Mitosis is part of the cell cycle.

Ex Output:
Mutations that lead to cancer usually occur in genes aiding in mitosis.


Ex Input:
Fact 1: a delta is formed by deposition of sediment at the mouth of a river by water fanning out. 
Fact 2: Erosion is responsible for wearing down exposed places and depositing sediment in level places.

Ex Output:
a delta is formed by erosion.


Ex Input:
Fact 1: being burried under soil and mud changes vegetation into peat through extreme heat and pressure in a swamp over a long period of time. 
Fact 2: Fossils are typically preserved when they are buried under many layers of sand and mud.

Ex Output:

being preserved under many layers changes vegetation into peat through extreme heat and pressure.