9. 다음 글의 내용과 일치하는 것은?

Sharks are covered in scales made from the same material as teeth. These flexible scales protect the shark and help it swim quickly in water. A shark can move the scales as it swims. This movement helps reduce the water's drag. Amy Lang, an aerospace engineer at the University of Alabama, studies the scales on the shortfin mako, a relative of the great white shark. Lang and her team discovered that the mako shark's scales differ in size and in flexibility in different parts of its body. For instance, the scales on the sides of the body are tapered―wide at one end and narrow at the other end. Because they are tapered, these scales move very easily. They can turn up or flatten to adjust to the flow of water around the shark and to reduce drag. Lang feels that shark scales can inspire designs for machines that experience drag, such as airplanes.

• 1
   A shark has scales that always remain immobile to protect itself as it swims.
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   Lang revealed that the scales of a mako shark are utilized to lessen drag in water.
• 3
   A mako shark has scales of identical size all over its body.
• 4
   The scientific designs of airplanes were inspired by shark scales.