On the main sequence, hot stars are generally than cool ones.
a. more massive and longer-lived
b. less massive and longer-lived
C. more massive and shorter-lived
d. less massive and longer-lived
e. more massive, but we don't know how long they live

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

there are no statements provided but here is why:

sulfur belongs to group 16 because it can be found in nature whether it is in a free or combined state.

hope this

it is b that is the answer.