Diffusion is the of particles from one region to another. It occurs because of two properties: the particles have between them and are able to . If we start off with two different particle types which are separated, and then the barrier which is separating them then will occur. The particles from both regions will and move in the spaces between other particles. The particles of each type will continue to mix until they are distributed. Diffusion can only happen with and because solid particles move around.

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day

the answer to this is proletariats.

hope this : )