Answer:
what scenario i dont understand
Explanation:
step by step explenation
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:
Distance between Ryan home and mountain will be 252 miles
Explanation:
Let the distance from home to mountains is d
It is given that it took 7 hours to go mountains from home
Let the speed in going to mountain is v
Then according to question speed in coming from mountain is v+27
And time taken in come from mountain to home is hour
As distance will be same in both case
Distance will be equal to 
So 

v = 36 miles per hour
So distance will be equal to 
When an object's atoms move faster, its thermal energy increases and the object becomes warmer.