Given a scientific question, generate a correct answer to it.

[Q]: Vertebrates. from the smallest of fish to us. one of the main features we all have in common is our what?
[A]: backbone

[Q]: Linked genes are located on the same what?
[A]: chromosome

[Q]: The ph scale is a scale used to express the concentration of hydrogen ions in solution. a neutral solution, neither acidic nor basic, has a ph of what?
[A]:
7