Scientific Investigation: SOL 2002

In 1928, the scientist Alexander Fleming was trying to grow the bacterium Staphylococcus, and by

chance, discovered that it would not grow in the presence of a mold that he

named Penicillium. In 1939, Ernst Chain and Howard Florey purified

penicillin, and in 1941, penicillin was first used to treat bacterial diseases. In 1945, Alexander Fleming, Ernst Chain, and Howard Florey received the Nobel Prize in medicine for the discovery and isolation of penicillin. These facts show that —

• Florey and Chain unfairly used Fleming’s work and should not have received the Nobel Prize

• chance plays no role in scientific discoveries

• scientific progress often requires the efforts of many people working together

• whenever possible, the Nobel Prize should be given to more than one person

Which of these hypotheses is best supported by observations of this animal?

• This animal spends much of its time digging.

• This animal usually hunts for food at night.

• This animal is herbivorous.

• This animal has poor hearing.

If a student needs to do research on heredity for a science project, which of these sources is the most reliable resource?

• A weekly news magazine

• A newspaper tabloid

• A national newspaper

• A professional journal

Which of these statements is best supported by these data?

• Wheat plants exposed to high-intensity ultraviolet light produce fewer seeds.

• Chloroplasts of wheat are able to filter out low-intensity ultraviolet light.

• High-intensity ultraviolet light may be used to control weed growth.

• No exposure to ultraviolet light increases pollination in wheat plants.

The picture shows the trachea and surrounding tissue of a flea. Which of these best describes the shape of the flea trachea?

• A single, coiled tube

• A double-helix shape

• A long, branched tube

• A six-sided cylinder

The data show the growth of two bean plants over several weeks using four different fertilizers. The experimental data would be more valid if which of the following variables was included in the experiment?

• A fifth fertilizer was tested.

• Only one plant was tested.

• The plants were grown at variable temperatures.

• A control without fertilizer was included for each plant.

The picture shows a model being used to explain how food is moved through the gastrointestinal (GI) tract. What do the fingers pushing the marble along represent?

• The pressure of blood vessels surrounding the GI tract

• The production of fluids by the GI tract

• The contraction of muscles in the GI tract

• The electrical impulses from the nervous

  system to the GI tract

The most valid and reliable test of this C hypothesis would include an experimental group of pine seeds that

was recovered from a fire area and pine seeds that were —

• germinated after a fire

• tolerant of fire

• found before a fire

• placed in a fire

A student wanted to study the effect of temperature on algae levels in a local stream. Which items are most useful for gathering data and most appropriate for communicating the results of her observations?

• Research on the Internet and videotapesof water samples

• Microscopes and written descriptions of weather patterns

• pH strips and written observations of stream water

• Test tubes, thermometers, and graphs of results

Jan consistently read the volume of liquids as shown. How would this practice impact her work?

• Her measurements would lack precision.

• Her measurements would be too high.

• Her measurements would be too low for less dense liquids.

• Her measurements would be very accurate.