There is a difference between a chemical mixture and a chemical compound. The properties of a mixture can vary because the amount of each material in the mixture is not always the same. A compound, however, is always composed of a definite amount of particular elements.

Which substance is a compound?

Reveal Solution Hide Solution

The shape and structure of the teeth in the mouth of an animal determine their function in obtaining its food. The broad, sharp incisors are used for biting. The long, pointed canine teeth are used for tearing food, while the molars, which have a larger surface area, are used for grinding food.

Exhibit:

In certain animals, the canine teeth are longer than other teeth.

Which of the following animals would be likely to have longer canines?

Reveal Solution Hide Solution

A clear container of hydrogen peroxide breaks down to form water and oxygen in approximately one month. When an enzyme known as catalase is added to hydrogen peroxide, water and oxygen are formed almost immediately.

Which of the following actions explains why this effect of catalase is typical of an enzyme?

Reveal Solution Hide Solution

Science is a systemized body of knowledge based on observation and experimentation. Technology involves applied science and the practical applications of scientific knowledge. The making of lenses for eyeglasses is a technology that is based on the scientific principles of optics explaining how light rays are bent by finely ground lenses.

Which example would be considered science rather than technology?

Reveal Solution Hide Solution

One wavelength is the distance from one crest of a wave to the next crest or from a trough (low point of a wave) to the next trough. The frequency of a wave is the number of crests that pass any given point each second.

Which of the following waves demonstrates the LOWEST frequency?

A)

B)

C)

D)

E)

Reveal Solution Hide Solution

Susan is studying air pressure and makes a simple mercury barometer as shown below. She knows that air exerts pressure. More pressure on the surface of the mercury in the bowl will cause the mercury level to rise. Less pressure will cause the mercury to fall. High barometric pressure is often associated with fair weather, and low barometric pressure is associated with rain.

Susan is enjoying a bright, sunny day when she hears a local weather forecaster predict rain for tomorrow.

When Susan checks her barometer tomorrow, which change is she most likely to note?

Reveal Solution Hide Solution

If a weight with a string attached is swung in a horizontal circular motion around in the air, the path of the weight will appear as shown in the figure at the left.

If the string breaks when the weight is at position A, the weight will fly away in a straight line tangent to the circular path.

In order for the weight to hit an object located at position X, the person should let go of the string when the weight is located at which position?

Reveal Solution Hide Solution

An autotroph is an organism that can make its own food. A heterotroph, an organism that is unable to make its food, relies on other living things for food and energy.

Which organism listed below could be classified as an autotroph?

Reveal Solution Hide Solution

A family wants to plant a garden, but the soil around the house is mainly clay. Clay soil easily becomes saturated with water, cutting off the air supply needed by plants. Adding sand and peat moss can help plants grow in clay soil.

Which is the procedure for preparing the clay soil for planting?

Reveal Solution Hide Solution

The digestive tract of an animal that eats meat is about four times the length of the animal’s body. In an animal that eats plants, the digestive tract is about twenty times the length of the animal’s body.

Which animal would be expected to have the longest digestive tract relative to its body length?

Reveal Solution Hide Solution