5.Sharks 1. Sharks are fast-swimming fish 2 that glide through water at speeds up to 40 miles an hour.

5. Sharks

1

Sharks are fast-swimming fish

2

that glide through water at speeds up to 40 miles an hour

Their graceful bodies are built for constant swimming and speed

3

Sharks’ skeletons are made of cartilage

A shark’s eyes are on the side of its head, and its mouth is on its underside

4

A shark’s body is covered with sharp, tooth-like scales

Shark skin is so rough that it can be used just like sandpaper

5

Most fish have a swim bladder

6

This is an organ that helps them float

Sharks do not have a swim bladder, instead they have large livers

7

The oil in their livers is lighter than water

which helps the shark float

Different sharks have different kinds of teeth

8

Sharks that eat fish have sharp, triangular teeth to catch and hold

their slippery prey

Sharks that eat shellfish have broad, flat teeth to crush shells.

9

Sharks that eat fish have sharp, triangular teeth to catch and hold

their slippery prey

Sharks that eat shellfish have broad, flat teeth to crush shells

10

Some sharks have several rows of teeth which are replaced

every few weeks

Behind the mouth are gill slits

11

When sharks swim, water is forced out the gill slits

Most sharks must swim all the time so they can use their gills to breathe

12

Sharks use their fins for steering and balance as they swim

Their tail and back fin push them through the water

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