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.
The primary purpose of the passage is to
Each nation has its own peculiar character which distinguishes it from others. But the people of the world have more points in which they are all like each other than points in which they are different. One type of person that is common in every country is the one who always tried to do as little as he possibly can and to get as much in return as he can. His opposite, the man who is in the habit of doing more than is strictly necessary and is ready to accept what is offered in return, is rare everywhere.
Both these types are usually unconscious of their character. The man who avoids effort is always talking about his ‘rights’; he appears to think that society owes him a pleasant easy life. The man who is always doing more than his sheer talks of ‘duties’ feels that the individual is in debt to society, and not society to the individual. As a result of their view, neither of these men thinks that he behaves at all strangely.
Which of the following thinks that the individual is in debt to the society?
The history of civilization shows how man always has to choose between making the right and wrong use of the discoveries of science. This has never been more true than in our own age. In a brief period amazing discoveries have been made and applied to practical purpose.
It would be ungrateful not to recognize how immense are the boons which science has given to mankind. It has brought within the reach of multitudes benefits and advantages which only a short time ago where the privilege of the few. It has shown how malnutrition, hunger and disease can be overcome. It has not only lengthened life but it has depended to his quality. Fields of knowledge, experience and recreation open in the past only to few, have been thrown open to million. Through the work of science the ordinary man today has been given the opportunity of a longer and fuller life than was ever possible to his grandparents.
Amazing discoveries of science have been made: