Fleas are perfectly designed by
nature to feast on anything containing blood. Like a shark in the water or a
wolf in the woods, fleas are ideally equipped to do what they do, making them
very difficult to defeat. The bodies of these tiny parasites are extremely
hardy and well-suited for their job.
A flea has a very hard exoskeleton,
which means the body is covered by a tough, tile-like plate called a sclerite.
Because of these plates, fleas are almost impossible to squish. The
exoskeletons of fleas are also waterproof of fleas are also waterproof and shock
resistant, and therefore fleas are highly resistant to the sprays and chemicals
used to kill them.
Little spines are attached to his
plate. The spine the flea scurries through an animal’s fur in – search of
grooming pet tries to pull a flea off through the hair coat, these spines will
extend and stick to the fur like Velcro.
Fleas are some of the best jumpers
in the natural world. A flea can jump seven inches, or 150 times its own
length, either vertically or horizontally. An equivalent jump for a person
would be 555 feet, the height of the Washington Monument. Fleas can jump 30,000
times in a row without stopping, and they are able to accelerate through the
air at an incredibly high rate – a rate which is over ten times what humans can
withstand in an airplane.
Fleas have very long rear legs with
huge thigh muscles and multiple joints. When they get ready to jump. They fold their
long legs up and crouch like a runner on a staring block. Several of their
joints contain a protein called resilin, which helps catapult fleas into the
air as they jump, similar to the way a rubber band provides momentum to a
slingshot. Outward facing claws on the bottom of their legs grip anything they
touch when they land.
The adult female flea mates after
her first blood meal and begins producing eggs in just 1 to 2 days. One flea
can lay up to 50 eggs in one day and over 2,000 in her lifetime. Flea eggs can
be seen with the naked eye, but they are about the size of a grain of salt. Shortly
after being laid, the eggs begin to transform into cocoons. In the cocoon
state, fleas are fully developed adults, and will hatch immediately if
conditions are favorable. Fleas can detect warmth, movement, and carbon dioxide
in exhaled breath, and these three factors stimulate them to emerge as new
adults. If the flea does not detect appropriate conditions, it can remain
dormant in the cocoon state for extended periods. Under ideal conditions, the
entire life cycle may only take 3 weeks, so in no time at all, pets and homes
can become infested.
Because of these characteristics,
fleas are intimidating opponents. The best way to control fleas, therefore, is
to take steps to prevent an infestation from ever occurring.
According to the passage, fleas are
able to jump
I with a high rate of acceleration
II up and down and from side to side
III because the blood they eat
contains resilin
Recent advances in science and technology have made it
possible for geneticists to find out abnormalities in the unborn foetus and
take remedial action to rectify some defects which would otherwise prove to be
fatal to the child. Though genetic engineering is still at its infancy,
scientists can now predict with greater accuracy a genetic disorder. It is not
yet an exact science since they are not in a position to predict when exactly a
genetic disorder will set in. While they have not yet been able to change the
genetic order of the gene in germs, they are optimistic and are holding out
that in the near future they might be successful in achieving this feat. They
have, however, acquired the ability in manipulating tissue cells. However,
genetic mis-information can sometimes be damaging for it may adversely affect
people psychologically. Genetic information may lead to a tendency to brand
some people as inferiors. Genetic information can therefore be abused and its
application in deciding the sex of the foetus and its subsequent abortion is
now hotly debated on ethical lines. But on this issue geneticists cannot be
squarely blamed though this charge has often been leveled at them. It is mainly
a societal problem. At present genetic engineering is a costly process of
detecting disorders but scientists hope to reduce the costs when technology
becomes more advanced. This is why much progress in this area has been possible
in scientifically advanced and rich countries like the U.S.A., U.K. and Japan.
It remains to be seen if in the future this science will lead to the
development of a race of supermen or will be able to obliterate disease from
this world.
Which of the following is not true, according to the
passage?
