There are more than 150 different kinds of sharks. Sharks differ
from other fish in some ways. ___1___
other fish have movable coverings over the gills, the sharks
have slits in their skins. A shark's skeleton, unlike a ___2___,
is made up of cartilage instead of bone. Sharks are fierce
hunters ___3___ roam
hundreds of kilometers looking for prey. They are strong swift
swimmers. Their sensitive noses can pick ___4___
the scent of blood spread by ocean currents. they can hear over
___5___ distances the
vibrations caused by injured fish. Sharks have rows of saw-edged
teeth designed for ___6___.
Most people think of sharks as very dangerous creatures. the
truth is that only some sharks are quite dangerous to humans.
Others are ___7___ Most
sharks eat only fish and molluscs.
The whale shark is the largest shark ___8___
it feeds only on plankton. The most dreaded of all sharks is the
great white shark. It ___9___
have no hesitation at all about making a meal out of a man. Then
there is the tiger shark. It ___10___
swallow a whole sea lion and has been known to attack human
beings. |