The term “jet stream” is often used by weather forecasters to describe

In reality, the border between hot and cold air. But meteorologists tend to misuse it and describe it as any strong upper-atmosphere wind pattern for simplicity.  

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