The layer of atmosphere that MOST planes fly in is called the troposphere.
MOLECULE: Smallest particle of a substance that has the properties of that substance (usually a compound); also, a particle composed of two or more atoms united by chemical bonds. PHYSICAL CHANGE: Any change in matter that does not destroy the identity of a substance, nor change its characteristic chemical properties.
Answer:
All of the above are correct.
Explanation:
The Flame Test Shortcomings
Small quantities of most molecules can not be measured by the examination.
The signal's intensity ranges from one test to the next.
The test findings are impaired by impurities or toxins.
The test is not capable of differentiating between all components.