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.

Example Input: Fact 1: recycling has a positive impact on the environment. 
Fact 2: Steel is a recycled and recyclable product.
Example Output: certain Steel products have a positive impact on the environment.

Example Input: Fact 1: a black hole is formed by a high-mass star collapses. 
Fact 2: Fundamentally, a black hole is invisible.
Example Output: a star collapsing can be invisible.

Example Input: Fact 1: Cells vary in size as well as shape, but all cells are very small. 
Fact 2: Lymphocytes in circulation are small cells.
Example Output:
lymphocytes are small.