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English home language

Grade 6

Module 8

Comprehension

COMPREHENSION

Read the following passage carefully and answer the questions orally:

DEADLY DENTURES

It's the height of the summer season. You are splashing about in the waves, without a care in the world. You dive under a breaker, and suddenly you see it. A monster shark, 20 ... no, 30 metres long! It approaches you with gaping jaws, revealing razor-sharp teeth the length of your hand. Aaarghhh!

The bad news is that this massive shark isn't a product of the human imagination, it's real. The good news is that it lived long long ago - even before Tyrannosaurus rex stamped across the land. So the only place you might encounter even a model of it is in a museum.

Fossils of enormous shark teeth, some of them exceeding 15 cm in length, have been dredged up from ocean floors. Some experts believe the owners may have been between 15m to 20m long; others put them at an awesome 30m.

Either way this ancient giant makes the infamous great white shark that prowls our modern oceans seem like child's play. The great white is a diminutive descendent of this prehistoric monster.

Teeth are the hallmark of sharks - as victims of shark bites demonstrate very clearly. In most sharks the mouth is on the underside of the head, although in a few species it is at the front. The powerful jaws, which are made of cartilage, are lined with several rows of teeth - in one species as many as 14.

However, only the front row is used at any one time to snatch a mouthful of flesh. The rows behind it are replacement teeth. Every week or so a new set of teeth moves forward to replace the front ones as they wear off or are lost by accident.

Shark teeth come in a variety of shapes, depending on the kind of food eaten. Most sharks, especially large hunters such as great white and tiger sharks, have roughly triangular teeth with pointed tips. In many, the teeth have serrated edges. They are used to cut through the skin, flesh and bones of victims and rip off large chunks of food. The tiger shark can even bite through turtle shells and crocodile skins.

Some sharks, on the other hand, have flat, molar like teeth used to crush and grind the hard shells of molluscs and crustaceans.

A few species such as whale and basking sharks are harmless plankton-eaters, which feed by straining food off the water through gill clefts. Their minute teeth, set in several rows, are used as a rough sort of file.

As though the teeth in their jaws are not enough, a shark’s skin is studded with thousands of sharp tiny teeth called "denticles".

Brush a shark's skin from head to tail, and it feels smooth. Brush it the other way, and it feels like sandpaper. Dried shark's skin, called shagreen, was once sold as sandpaper for polishing wooden furniture.

The bad reputation sharks have, though, is largely undeserved. For one thing, most are harmless to people. For another, attacks on humans by large predatory sharks are comparatively rare - many more people die from drowning every year than from shark wounds.

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Good
Berger describes sociologists as concerned with
Mueller Reply
what is hormones?
Wellington
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Source:  OpenStax, English home language grade 6. OpenStax CNX. Sep 07, 2009 Download for free at http://cnx.org/content/col10997/1.1
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