Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

[Q]: Question: A mammal that reproduces by laying eggs is called what? Answer: monotreme
[A]: Platypus. The platypus is a monotreme, a mammal that reproduces by laying eggs.

[Q]: Question: What long molecules are composed of chains of units called monomers? Answer: polymers
[A]: Polymers are long molecules composed of chains of units called monomers.

[Q]: Question: What catalyst substances may also allow reactions to occur by different pathways that have lower activation energy? Answer: enzymes
[A]:
Enzymes may also allow reactions to occur by different pathways that have lower activation energy.