Key points about each:


2. A scientist is conducting a study to determine how well a new medication treats ear infections. The scientist tells the participants to put 10 drops in their infected ear each day. After two weeks, all participants' ear infections had healed. Which of the following changes to the design of this study would most improve the ability to test if the new medication effectively treats ear infections?

Have participants put ear drops in both their infected ear and healthy ear

Create a second group of participants with ear infections who do not use any ear drops

Have participants use ear drops for only one week

Create a second group of participants with ear infections who use 15 drops a day

Next

3. Which of the following is an example of genetic engineering?

Attaching the root of one type of plant to the stem of another type of plant

Growing a whole plant from a single cell

Finding the sequences of bases in plant DNA

Inserting a gene into plants that makes them resistant to insects


4. What is the main cause of seasons on the Earth?

Changes in the amount of energy coming from the sun

The distance between the Earth and the sun

The speed that the Earth rotates around the sun

The tilt of the Earth's axis in relation to the sun


5. These graphs show the monthly precipitation and average temperature for three cities in the United States over the course of one year. Based on the graphs, which city has the greatest annual range of temperatures?

They all have the same annual temperature range

Chicago, Illinois

Los Angeles, California

New York, New York

Next 

6. The time a computer takes to start has increased dramatically. One possible explanation for this is that the computer is running out of memory. This explanation is a scientific…

Observation

Hypothesis

Experiment

Conclusion


7. Many diseases have an incubation period. Which of the following best describes what an incubation period is?

The recovery period after being sick

The period during which someone has an infection, but is not showing symptoms

The effect of a disease on babies

The period during which someone builds up immunity to a disease


8. When large areas of forest are removed so land can be converted for other uses, such as farming, which of the following occurs?

Colder temperature

Increased erosion

Greater oxygen production

Decreased carbon dioxide


9. An antacid relieves an overly acidic stomach because the main components of antacids are …

Acids

Isotopes

Neutral

Bases

An antacid relieves an overly acidic stomach because the main components of antacids are bases. 

Explanation: Bases neutralize acids, so when an antacid (which is a base) comes into contact with stomach acid, it neutralizes it, reducing the acidity level. 

Key points:

10. Which of these is a major concern about the overuse of antibiotics?

Antibiotics can cause secondary infections

Antibiotics will get into the water system

There will be an antibiotic shortage

It can lead to antibiotic-resistant bacteria


11. A car travels at a constant speed of 40 miles per hour. How far does the car travel in 45 minutes?

25 miles

30 miles

35 miles

40 miles