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: Lancelet larvae are free-swimming. 
Fact 2: Some types of snails are free swimming, while others are sessile.

A: lancelet larvae are not sessile.
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Q: Fact 1: if heat is conducted to an object then that object will become hot. 
Fact 2: Insulation helps to block conduction of heat.

A: Insulation helps block conduction to an object.
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Q: Fact 1: wind and rain cause erosion. 
Fact 2: Water, in the form of rain, is the most effective agent of erosion.

A:
water causes erosion most effectively.
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