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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

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
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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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