instruction:
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.
question:
Fact 1: plant reproduction requires pollination. 
Fact 2: Bees are necessary for pollination.
answer:
plant reproduction requires bees.


question:
Fact 1: sweat is used for adjusting to hot temperatures by some animals. 
Fact 2: Perspiration is produced by sweat glands in the skin and is secreted through pores.
answer:
Perspiration is used for adjusting to hot temperatures by some animals.


question:
Fact 1: Hair is a fiber that is found only in mammals. 
Fact 2: Hair is largely made of keratin, a protein that contains a lot of the amino acid cystine .
answer:

mammals contain keratin.