Science STAAR Practice

Many people ride a bicycle for fun and exercise. Some people ride a bicycle to work because it saves money and benefits the environment by reducing the use of fossil fuels. Which of these is not an example of the bicycle using mechanical energy?

• The pedals, gears, and chain help turn the wheels.

• The wheels turn when the bicycle moves.

• The front wheel guides the bicycle as it moves.

• The reflector allows the bicycle to be seen at night.

A farmer keeps bees to pollinate crops. The farmer makes several observations about the bees. Which of these observations describes a learned behavior?

• Bees make return trips to drink sugar water from a bowl placed 40 meters from their hive.

• Bees have dark eyes and black-and-yellow stripes.

• Bees produce honey from the nectar they collect.

• Bees will sting when threatened or disturbed.

The whiskers of a river otter and the antennae of a cockroach are shown here. How do structures such as whiskers and antennae benefit organisms?

• They help the organisms detect their surroundings.

• They help the organisms eat food quickly.

• They help the organisms fight predators.

• None of these

An energy company wants to build a hydroelectric power plant. Which of these characteristics of an area is most important to the development of a hydroelectric power plant?

• The area has a cool, rainy climate.

• The area is located in a valley with very little wind and frequent heavy fog.

• The area has a river that flows rapidly from nearby mountains through a valley.

• The area has no geysers or hot springs.

Some students investigate the properties of four objects using a hand lens, a magnet, and a beaker containing water. Their observations are recorded in the table. Which statement identifies a property that could be used to classify these objects into two different groups?

• Density can be used to separate objects that sink in water from objects that do not.

• Magnetism can be used to separate objects that are attracted by a magnet from objects that are not.

• Solubility can be used to separate objects that dissolve in water from objects that do not.

• Physical state can be used to separate objects that are solids from objects that are not.

An African savanna is a grassland with shrubs and a few small trees. It has warm temperatures all year long, a dry winter season, and a rainy summer season. Which group of animals is most likely supported by an African savanna?

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Some characteristics of objects in the solar system are listed here. Which of the listed characteristics describe both Earth and the moon?

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The table shown lists ways that four organisms obtain energy. Which organism obtains energy without depending on another organism?

• Oak tree

• Mushroom

• Cottontail rabbit

• Mountain Lion

A student observed liquid wax dripping down the side of a burning candle. After putting out the candle’s flame, the student left the room. Several hours later the student observed that there was no longer any liquid on the side of the candle. Which statement explains what most likely happened to the liquid wax?

• The heat given off by the flame caused the candle wax to evaporate.

• The liquid wax changed back into a solid as it cooled.

• The liquid wax condensed and was absorbed by the candle.

• None of the above

Which statement best describes the relationship between humans and plants in the carbon dioxide–oxygen cycle?

• Humans depend on oxygen released into the air by plants, and plants depend on carbon dioxide that humans release into the air.

• Plants produce carbon dioxide as a product of photosynthesis and release it into the air to provide energy for humans.

• Plants depend primarily on energy supplied by oxygen for photosynthesis, a process which releases carbon dioxide needed by humans.

• Humans and plants use gases in the air and the energy of sunlight to produce their own food.