### 3.1 Sets & Set Diagrams

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• Math Help

In the set diagram on page 107, the fish class is drawn as the complement of the union of birds, amphibians, mammals, and vertebrates.

• Consumer Suggestion

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• Checkpoint Solution

Here is one possible set diagram for this information.

Note that for the purpose of illustration, we have classified fish (like sharks) that have cartilage skeletons as vertebrate. Sharks and other cartilaginous fish (skates and rays) have skeletons made of cartilage and connective tissue. Cartilage has about half the density of bone. This reduces the skeleton's weight, saving energy.

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``` _    _     _____     _  __     ___     _____
| \  / ||  |  ___||  | |/ //   / _ \\  |  __ \\
|  \/  ||  | ||__    | ' //   / //\ \\ | |  \ ||
| .  . ||  | ||__    | . \\  |  ___  ||| |__/ ||
|_|\/|_||  |_____||  |_|\_\\ |_||  |_|||_____//
`-`  `-`   `-----`   `-` --` `-`   `-`  -----`

```