A student sitting in the back row opened a bottle of foul-smelling perfume and dabbed it on her wrists. One by one (beginning from the back of the room), the students began to cough due to the foul smell. This phenomenon was due to
A) osmosis.
B) molecules moving from an area of low concentration to high concentration.
C) an allergic reaction.
D) diffusion.
E) active transport.

Question

Quizplus · Accepted Answer

The act of the molecules moving from an area of high concentration (the perfume on the student's wrist) to an area of low concentration (other parts of the room) is diffusion. This is what caused the foul smell to spread, and it is why the students began to cough one by one, starting from the back of the room.

A Student Sitting in the Back Row Opened a Bottle