The air in the troposphere is a(n)

element
compound
mixture

The answer is mixture. A mixture is a substance that is composed of a combination of different elements that are not chemically combined (and can be physically separated). The troposphere is the lowest layer of the earth’s atmosphere and where the weather condition occurs. This means the air is mixed with water vapor (that form clouds) and other impurities such as dust and aerosols.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e