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.

Input: Consider Input: Fact 1: volcanic ash in the atmosphere decreases the temperature by blocking the sun. 
Fact 2: Or a veil of tiny particles from a volcanic eruption can block the sun.

Output: volcanoes can block the sun.


Input: Consider Input: Fact 1: Protozoa can be classified on the basis of how they move. 
Fact 2: For ease of identification, cotton seedlings are classified into the following three categories.

Output: Protozoa can be identified by how they move.


Input: Consider Input: Fact 1: Air pollution harms the respiratory and circulatory systems. 
Fact 2: Exposure to ozone can diminish lung function and increase susceptibility to respiratory infection.


Output: Exposure to air pollution can harm the lungs.