The Progress of Scientific Knowledge — Unit test Answers

Researchers conducted an experiment to identify the effects of three different hand sanitizers on the growth of bacteria. The researchers grew one type of bacteria in twenty-four identical covered petri dishes. Then, they opened eighteen petri dishes and applied the three hand sanitizers to six petri dishes each. They left the remaining six petri dishes closed as a control group. When the researchers measured the growth of bacteria two days later, the six dishes that had no hand sanitizer showed the least amount of bacterial growth. The researchers concluded that not using any hand sanitizer would lead to the least bacterial growth. Which statement best explains why the researchers’ conclusion was not justified?

A teacher discusses a scientific theory that has been in place for almost a century. Which would present the greatest challenge to this theory?

Hybrid seeds are deliberately crossbred for particular traits, such as growth pattern or disease resistance. They have been hand-pollinated and are patented, often sterile, and genetically identical within food types. These plants are usually grown in a monocultural environment and are cultivated for mass production and sale. They must be sturdy to withstand mechanical picking and cross-country shipping. They do not compare to the quality and taste of heirloom plants, but they do produce large, healthy fruit that appeals to most shoppers. Unlike heirloom seeds, if one saves a hybrid seed, one will not get the same plant again. Which statement can be removed and not affect the excerpt’s reliability?

Which is a type of irradiation used to prevent food-borne illnesses?

A filmmaker wants to depict a realistic dramatization of a scientist making and communicating an important scientific discovery. Which plot description would best depict the methods of discovery and communication that a modern professional scientist uses?

A food web diagrams the interactions between organisms based on which organisms others are eating. A scientist is using a food web to predict the predator-prey relationship of a population. What can a food web best be classified as?

In double-blind studies neither the test subject or the researcher knows who was given the drug and who was given the control. Why are these studies effective for testing a drug that may elevate mood and relieve feelings of depression?

Measurements that are close to the correct value are

Doctors are seeing an alarming increase in the number of cases of tuberculosis (TB) that is resistant to drugs commonly used to treat the disease. TB is difficult to pass to other people without prolonged contact, but it is often fatal if it is not treated. How will doctors most likely respond to someone who has an active case of drug-resistant tuberculosis?

Which best explains why openness is important to the progress of science?

A recent encyclopedia entry about dogs cites multiple research papers done by scientists at veterinary schools. According to the article, Labrador retrievers come in two specific breeds: English and American. The English breed is described as stocky and heavy, while the American breed is described as tall and lanky. The article describes current scientific research as showing that males of both breeds usually weigh about 29-41 kg (65-90 lb), and females weigh 25-32 kg (55-70 lb). Coat colors for both breeds come in solid black, yellow, or chocolate. All labs have strong tails and webbed feet, which help them swim. Devon would like to use this information to determine if his new dog is an English or American Labrador retriever. Which best describes the reliability of the information?

When analyzing the results of a scientific experiment, Kevin should base his conclusion on

Which best describes Internet wikis as a source of scientific information?

Pasteurization is a process that heats milk to remove disease-causing organisms. It does not change the nutritional value or taste of the milk. Some other foods can also be pasteurized. However, if meat is heated, its quality, including taste, change. Which was developed to allow for a similar effect without the loss of food quality?

A commonly held idea about influenza is that it is a disease that occurs primarily in cold weather. Doctors report incidences of illness, such as influenza, to the Centers for Disease Control (CDC). The graph below shows data for three flu seasons. Note that this graph shows data from October, week 40, of one year to July, week 28, of the following year.Which evidence supports this idea?

Mendel reached conclusions about inheritance without ever seeing chromosomes or knowing about DNA. Which technology has enabled the greatest advances in understanding inheritance?

X-ray crystallography is used to see the structure of molecules. Scientists have used this technique to find the structure of cholesterol, an important biological molecule. Knowledge of the structure of cholesterol is helpful because it may affect

In 1971, a physicist named Gabor received the Nobel Prize for developing the basic ideas of holography, a method of producing a three-dimensional image of an object. His work marked a major advance in laser technology and occurred without much previous work in this area. Based on this information, which statement is most likely true of Gabor?

HIV, the virus that causes AIDS, is transferred through body fluids. People once thought that HIV infections were untreatable. Now, many people live relatively long and healthy lives despite being infected with HIV. This is possible because science helped

A scientist told his student assistants that he had sorted groups of mice by their intelligence and asked the assistants to assess the groups’ maze-solving abilities. The scientist had not actually sorted the mice by intelligence. The students rated the “highest intelligence” group of mice as the best maze solvers and the “lowest intelligence” group as the worst maze solvers. What was the scientist trying to demonstrate by doing this experiment?