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The term bacteria was devised in the 19th century by German biologist Ferdinand Cohn. He based it on the Greek word "bakterion" meaning a small rod or staff. Cohn is considered to be the father of modern bacteriology.

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In 1835 it was discovered that a disease of silkworms known as muscardine could be transferred from one silkworm to another, and was caused by a fungus.

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The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.

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There can actually be a 25-hour time difference between certain locations in the world. The International Date Line passes between the islands of Samoa and American Samoa. It is not a straight line, but "zig-zags" around various island chains. Therefore, Samoa and nearby islands have one date, while American Samoa and nearby islands are one day behind. Daylight saving time is used in some islands, but not in others—further shifting the hours out of sync with natural time.

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Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.

Traniello and his colleagues demonstrated that social insects may develop “social imm Traniello and his colleagues demonstrated that social insects may develop “social imm
A fixed action pattern as an example of innate behaviour. A fixed action pattern as an example of innate behaviour.
Immunization with a vaccine. A healthcare professional is injecting a vaccine into the patient’s arm Immunization with a vaccine. A healthcare professional is injecting a vaccine into the patient’s arm
Types of immunity. Types of immunity.
Types of Immunity Types of Immunity
Innate Defenses Innate Defenses
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