I know air at higher elevations to be thinner. If that answer isn't useful. I'm sorry.
I think its B
hope it helps
Answer:
incorrect
Explanation:
diffusion is the movement of particles <u>with</u> the concentration gradient
for example: over time, food coloring and water mix and become one same color.
1 and three ........................
It's the 4 the answer I hope it has served you
