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.
Using the information in the passage
as a guide, it can be concluded that
Chocolate – there’s nothing quite like it, is there?
Chocolate is simply delicious. What is chocolate? Where does it come from?
Christopher Columbus was probably the first to take cacao
beans from the New World to Europe in around 1502. But the history of chocolate
goes back at least 4,000 years! The Aztecs, who lived in America, through that
their bitter cacao drink was a divine gift from heaven. In fact, the scientist
Carolus Linnaeus named the plant Theobroma, which means “food of the gods”
The Spanish explorer Hernando Cortex went to America in
1519. He visited the Mexican emperor Montezuma. He saw that Montezuma drank
cacao mixed with vanilla and spices. Cortez took some cacao home as a gift to the
Spanish King Charles. In Spain, people began to drink Cortez’s chocolate in
drink with chili peppers. However, the natural taste of cacao was too bitter
for most people. To sweeten the drink, Europeans added sugar to the cacao
drink. As a sweet drink, it became more popular. By the 17th
century, rich people in Europe were drinking it.
Later, people started using chocolate in pastries, like pies and cakes. In 1828, Dutch chocolate
makers started using a new process for removing the fat from cacao beans, and
getting to the center of the cacao bean. The Dutch chocolate maker Conrad J.
Van Houten made a machine that pressed the fat from the bean. The resulting powder
mixed better with water than cacao did. Now, some call van Houten’s chocolate “Dutch
chocolate.”
It was easy to mix Dutuch chocolate powder with sugar. So
other chocolate makers started trying new recipes that used powdered chocolate. People started
mixing sweetened chocolate with cocoa butter to make solid chocolate bars. In
1849, an English chocolate maker made the first chocolate bar. In the 19th
century, the Swiss started making milk chocolate by mixing powdered milk with
sweetened chocolate. Milk chocolate has not changed much since this process was
invented.
Today, two countries – Brazil and Ivory Coast – account for
almost half the world’s chocolate. The United States imports most of the
chocolate in the world, but the Swiss eat the most chocolate per person. The
most chocolate eaten today is sweet milk chocolate, but people also eat white
chocolate and dark chocolate.
Cocoa and dark chocolate are believed to help prevent heart
attacks, or help keep from happening. They are supposed to be good for the
circulatory system. On the other hand, the high fat content of chocolate can
cause weight gain, which is not good for people’s health. Other health claims
for chocolate have not been proven, but some research shows that chocolate
could be good for the brain.
Chocolate is a popular holiday gift. A popular Valentine’s
Day gift is a box of chocolate candies with a card and flowers. Chocolate is
sometimes given for Christmas and birthdays. Chocolate eggs are sometimes given
at Easter.
Chocolate is toxic to some animals. An ingredient in chocolate
is poisonous to dogs, cats, parrots, small rodents, and some livestock. Their
bodies cannot process some if the chemicals found in chocolate. Therefore, they
should never be fed chocolate.
What are recipes?
