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.
Based on information in the passage,
the reader can understand that
When her grandmother’s health began to deteriorate in the
fall of 1994, Mary would make the drive from Washington, DC to Winchester every
few days.
She hated highway driving, finding it ugly and monotonous. She
preferred to take meandering back roads to her grandmother’s hospital. When she
drove through the rocky town of Harpers Ferry, the beauty of the rough waters
churning at the intersection of the Shenandoah and Potomac rivers always
captivated her.
Toward the end of her journey, Mary had to get on highway
81. It was here that she discovered a surprising bit of beauty during one of
her trips. Along the median of the highway, there was a long stretch of
wildflowers. They were thin and delicate and purple, and swayed in the wind as
if whispering poems to each other.
The first time she saw the flowers, Mary was seized by an uncontrollable
urge to pull over on the highway and yank a bunch from the soil. She carried
them into her grandmother’s room when she arrived at the hospital and placed
them in a water pitcher by her bed. For a moment her grandmother seemed more
lucid than usual. She thanked Mary for the flowers, commented on their beauty
and asked where she had gotten them. Mary was overjoyed by the ability of the
flowers to wake something up inside her ailing grandmother.
Afterwards, Mary began carrying scissors in the car during
her trips to visit her grandmother. She would quickly glide onto the shoulder,
jump out of the car, and clip a bunch of flowers. Each time Mary placed the
flowers in the pitcher, her grandmother’s eyes would light up and they would
have a splendid conversation.
One morning in late October, Mary got a call that her
grandmother had taken a turn for the worse. Mary was in such a hurry to get to
her grandmother that she sped past her flower spot. She decided to turn around
head several miles back, and cut a bunch. Mary arrived at the hospital to find her
grandmother very weak and unresponsive. She placed flowers in the pitcher and
sat down. She felt a squeeze on her fingers. It was the last conversation they
had.
Which best describes what the act of stopping for flowers on
the side of the highway became for Mary?
This is the age of machine.
Machines are everywhere, in the fields, in the factory, in the home, In the
street, in the city, in the country, everywhere. To fly, it is not necessary to
have wings; there are machines. To swim under the sea, it is not necessary to
have gills; there are machines. To kill our fellowmen in over-whelming numbers,
there are machines. Petrol machines alone provide ten times more power than all
human beings in the world. In the busiest countries, each individual has six
hundred human slaves in his machines.
What
are the consequences of this abnormal power? Before the war, it looked as
though it might be possible, for the first time in history to provide food and
clothing and shelter for the teaming population of the world-every man, woman
and child. This would have been the greatest triumphs of science. And yet, if
you remember, we saw the world crammed, full of food and people hungry. Today,
the leaders are bare and millions, starving. That’s more begin to hum, are we
going to see again more and more food, and people still hungry? For the goods,
it makes the goods, but avoids the consequences.
The
machine age produces:
