Which is a characteristic of colloids? a. are homogenous mixtures
b. have large dispersed particles
c. will settle out over time
d. are made up of at least two substances

D

The definition of colloids is very disputed on whether or not it is homo/heterogenous. I wouldn't go with this answer, but its based on what you learned it was. At a microscopic level its hetero but at a macroscopic its homo.

They do have somewhat large dispersed particles but this better describes suspensions

They don't easily settle out.

And in order to be a mixture, they are made up of at least two substances

D is likely the best answer out of the bunch.