Skill 1-2

EXERCISE (Skills 1-2): Study each of the passages and choose the best answers to the questions that follow.

PASSAGE ONE (Questions 1-2)

Common types of calendars can be based on the Sun or on the Moon. The solar calendar is based on the solar year. Since the solar year is 365.2422 days long, solar calendars consist of regular years of 365 days and have an extra day every fourth year, or leap year, to make up for the Line additional fractional amount. In a solar calendar, the waxing and waning of the Moon can take (5) place at various stages of each month.

The lunar calendar is synchronized to the lunar month rather than the solar year. Since the lunar month is twenty-nine and a half days long, most lunar calendars have alternating months of twenty-nine and thirty days. A twelve-month lunar year thus has 354 days, 1 1 days shorter than a solar year.

PASSAGE TWO (Questions 3-4)

Vaccines are prepared from harmful viruses or bacteria and administered to patients to provide immunity to specific diseases. The various types of vaccines are classified according to the method by which they are derived. Line The most basic class of vaccines actually contains disease-causing microorganisms that have (5) been killed with a solution containing formaldehyde. In this type of vaccine, the microorganisms are dead and therefore cannot cause disease; however, the antigens found in and on the microorganisms can still stimulate the formation of antibodies. Examples of this type of vaccine are the ones that fight influenza, typhoid fever, and cholera.

A second type of vaccine contains the toxins produced by the microorganisms rather than (10) the microorganisms themselves. This type of vaccine is prepared when the microorganism itself does little damage but the toxin within the microorganism is extremely harmful. For example, the bacteria that cause diphtheria can thrive in the throat without much harm, but when toxins are released from the bacteria, muscles can become paralyzed and death can ensue.

A final type of vaccine contains living microorganisms that have been rendered harmless.
(15) With this type of vaccine, a large number of antigen molecules are produced and the immunity that results is generally longer lasting than the immunity from other types of vaccines. The Sabin oral antipolio vaccine and the BCG vaccine against tuberculosis are examples of this type of vaccine.

PASSAGE THREE (Questions 5-6)

A hoax, unlike an honest error, is a deliberately-concocted plan to present an untruth as the truth. It can take the form of a fraud, a fake, a swindle, or a forgery, and can be accomplished in almost any field: successful hoaxes have been foisted on the public in fields as varied as politics, Line religion, science, art, and literature. (5) A famous scientific hoax occurred in 1912 when Charles Dawson claimed to have uncovered a human skull and jawbone on the Piltdown Common in southern England. These human remains were said to be more than 500,000 years old and were unlike any other remains from that period; as such, they represented an important discovery in the study of human evolution. These remains, popularly known as the Piltdown Man and scientifically named Eoanthropus dawsoni after (10) their discoverer, confounded scientists for several decades.

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