QUESTION: 165

The waters of the Antarctic region contain an abundance of animal and plant life. The large number of living organisms stems partly from the water's high mineral content and partly from the constant cold temperature. The continual flow of materials from below brings nitrates and phosphates into the surface zone. Cold water holds more dissolved carbon dioxide and oxygen than does warm water. The abundance of carbon dioxide and the available sunlight allow photosynthesis to occur in the surface waters almost continuously during the long daylight hours in the summer.
If the temperature of the Antarctic waters increased by a marked degree, which of the following statements would explain a decrease in the abundant life there now?

In warm water, oxygen and carbon dioxide combine to form ammonia and other poisonous gases.
Warm water evaporates much more slowly than cold water.
Warm water contains less dissolved carbon dioxide needed for photosynthesis.
Minerals dissolve more readily in cold water.
Warm water contains more oxygen than cold water.

Answer(s): C

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QUESTION: 166

In the diagram below, the shaded parts show how much water each boat displaces as it floats. Boat B weighs more than boat A, since it has more people aboard. Boat B displaces more water than does boat A. For floating to happen, the weight of the water displaced has to be equal to the weight of the floating boat.
-- Exhibit --
In the diagram below, the shaded parts show how much water each boat displaces as it floats. Boat B weighs more than boat A, since it has more people aboard. Boat B displaces more water than does boat A. For floating to happen, the weight of the water displaced has to be equal to the weight of the floating boat.

-- Exhibit --
Flood waters do not have to be very deep to float a car. In fact, only two feet of water, about knee high, will float the average car.
Which statement BEST explains why a car floats in such a small amount of water?

The car is not equipped with four wheel drive.
The car's center of gravity is at the two foot line.
The weight of water that the car displaces is the same as the weight of the whole car.
The water makes the road surface too slick for the car to maintain traction, increasing the braking distance.
The car is not equipped with an automatic transmission.

Answer(s): C

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QUESTION: 167

The atmosphere exerts a certain amount of air pressure on all objects on Earth. The air pressure at a specific location varies with the temperature, the distance above sea level, the amount of air present, and other factors.
In the demonstration above, a student places two ounces of water in an empty 12-ounce soda can and heats it on a hot plate until steam forms. Then the can is immediately inverted into a pan of cold water. The steam inside the can condensed, creating a vacuum.
Almost immediately, the can collapses.
Based on the information,

which statement provides the best explanation for this occurrence?