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: Complex chemistry is needed to carry out all the functions of life. 
Fact 2: Steroids are complex proteins needed to control the bodies chemistry.
Steroids are needed to control life functions.

Fact 1: Platypus females lay their eggs in a burrow. 
Fact 2: Like the platypus, it is an egg laying mammal.
some mammals lay their eggs in a burrow.

Fact 1: having no natural predators increases population size. 
Fact 2: With an increase in population there is an increase in expenditures.

having no natural predators increases expenditures.