GED-Science 무료 덤프문제 온라인 액세스

Some work is converted into heat whenever there is friction. For example, when you rub your hands together, they feel warm because of the friction. The same effect occurs when an automobile axle spins on ball bearings-the axle and bearings get hot.
A mechanic says that the heat produced will be decreased if grease is deposited between the bearings and the axle.
Which of the following statements would provide the strongest support for the mechanic's claim?

• A.Grease decreases friction.
• B.Grease decreases the speed of the axle.
• C.Grease is hot and adds heat.
• D.Grease makes the bearings stick to the axle.
• E.Grease increases friction.

A cell, the basic unit of living things, contains microscopic structures called organelles. A group of specialized cells of the same type forms a tissue, such as muscle or nerve tissue. An organ such as the liver is composed of different kinds of tissues that contribute to its overall function. A group of related organs form an organ system, such as the digestive system. A living organism may contain a number of organ systems working together to carry on the life functions.
Based on the information, in which category does the human heart belong?

• A.tissue
• B.organ system
• C.cell
• D.organ
• E.organelle

During an electrical storm, a lightning flash is seen before the sound of thunder that it generated can be heard. The farther a person is from the storm, the greater the time interval between the light flash and the arrival of the sound. Which of the following statements best explains this phenomenon?

• A.Lightning consists of a flash of light followed by a loud sound.
• B.Light travels faster than sound.
• C.Electricity can travel rapidly in the Earth's atmosphere.
• D.The density of the atmosphere decreases the speed of light.
• E.Sound travels somewhat faster than light.

Refer to the following information and table.
The table below indicates the results of a preliminary study of a flu medication (RX). The subjects were randomly selected groups of males, ages 50-70, residing in a North American city with a population of more than one million people.
Exhibit:

Based on the data in the chart and the information provided, which treatment appeared to be most effective in treating the early stages of the flu in these subjects?

• A.B
• B.A
• C.E
• D.C
• E.D

Exhibit:

Based on the information, which statement is NOT true of the Gammarus?

• A.are part of the food chain
• B.are primarily fresh water organisms
• C.are able to make their own food
• D.have structures often related to their function
• E.are helpful in assessing some pollutants