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.

Fact 1: Cells are programmed to divide only a set number of times. 
Fact 2: Cells reproduce asexually, by dividing.
Cells are programmed to reproduce only a set number of times.

Fact 1: a mold spore has a negative impact on the respiratory system. 
Fact 2: Insects also have both a heart and a respiratory, or breathing, system.
a mold spore has a negative impact on breathing.

Fact 1: Earthworms are important deposit feeders that help form and enrich soil. 
Fact 2: Earthworms Earthworms are in the phylum Annelids.

annelids enrich the soil.