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: a plant requires water to grow. 
Fact 2: Clouds form by the condensation of water vapor.

A: a plant requires Clouds to grow.
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Q: Fact 1: Butter is a fat that is a solid at room temperature. 
Fact 2: Some fats are more likely to cause heart disease.

A: butter can lead to heart disease.
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Q: Fact 1: Birds are endothermic tetrapod vertebrates. 
Fact 2: Legs define Tetrapods.

A:
Birds are endothermic vertebrates with legs.
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