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.

[Q]: Fact 1: Most invertebrates have a more complex nervous system. 
Fact 2: Cephalopods have the most advanced nervous systems of all invertebrates.
[A]: Cephalopods have a complex nervous system.


[Q]: Fact 1: sound can be used for communication by animals. 
Fact 2: Sound occurs when a body, such as a vocal chord, vibrates, or moves back and forth.
[A]: Animals may use vocal chords to communicate.


[Q]: Fact 1: Sperm had to swim from male to female reproductive organs for fertilization. 
Fact 2: And slow sperm is one of the leading causes of male infertility .
[A]:
slow sperm may not swim fast.