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.

Q: 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.

A: volcanoes can block the sun.
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Q: Fact 1: changes in the pH of soil can cause plants to die. 
Fact 2: Sulfur lowers pH in soil.

A: Adding sulfer to soil can cause plants to die.
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Q: Fact 1: better senses have a positive impact on an animal 's survival. 
Fact 2: An antelope has such a fine sense of hearing that it senses danger long in advance.

A:
An antelope's excellent hearing helps it survive.
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