Answer:
D. Test a piece of treated iron and a piece of untreated iron under the same conditions.
Explanation:
A controlled experiment is defined as an experiment where the experimenter or the researcher tries to test or experiment his result by changing one variable at a time and keeping the other factors under the same conditions and sees how it effects the result.
The factors which can be changed in an experiment is called its variables.
In the context, testing a piece of treated iron as well as a untreated piece of iron under the same working conditions forms a controlled experiment.
Answer:
25 x 9/5 = 45 degrees Fahrenheit
Explanation:
Because of the opposing forces on the car like friction because there is no more acceleration
Answer:
As ailtitudes rises air pressure drops ...... As altitude increases , the amount of gas molecules in the air decreases - so the air becomes less dense than air nearer to the sea level. So there is less air pressure at high altitudes
