Write a fact related to the given fact, based on the given topic word. Note that, your fact should have at least one word in common with the given fact. All facts in this task refer to scientific facts. Your related fact must form a chain with the given fact. Chains form when two facts connect together to produce the third fact. An example of a chain is: "pesticides cause pollution" (given fact) + "pollution can harm animals" (related fact) → "pesticides can harm animals" (connected chain). Avoid creating simple paraphrases of the given fact. While your generated fact should be related to the input fact, they must describe slightly different scientific phenomena. It's okay if your related fact includes some irrelevant information, provided that it has some overlap with the given fact and it contains some words corresponding to the provided topic.

[Q]: Fact: competition may cause animals to fight towards members of their own species. 
Topic: humans animals.
[A]: Humans are animals too.


[Q]: Fact: Food consists of organic molecules that store energy in their chemical bonds. 
Topic: chemical bonds.
[A]: Chemical bonds are electrical in nature.


[Q]: Fact: Mutualism is a symbiotic relationship in which both species benefit. 
Topic: species living beings.
[A]:
Out of the 8,400,000 different species of living beings, there are 400,000 human species.