Until now it is estimated U.S. coal production totaled about 9.1 million short tons (MMst) 27%lower than last year.
East of mississippi river totaled 3.7 MMst
West of mississippi river totaled 5.4 MMst
The supply of both types of coal is expected to decline as production from Appalachia falls from 201.5 million tons in 2018 to 170.1 million tons in 2020.
Therefore, a 10x eyepiece used with a 40X objective lens, will produce a magnification of 400X. The naked eye can now view the specimen at a magnification 400 times greater and so microscopic details are revealed. More on objective lenses here. Magnification is the ability to view an object as larger.
Answer:
1. It was a control variable
2. Type of insulation
3. Temperature
4. Plastic lids <em>or </em>Water <em>or </em>Half Full <em>or </em>Direct Sunlight