Explain the difference between unilinealism and diffusion.

Unilinealism is the social theory in which different social status is aligned in a single line that moves from most primitive to most civilized.

and

Diffusion is the spreading of something more widely.

Explanation:

so the answer is that Unilinealism is social theory, and Diffusion is just a spreading... nothing more, nothing less!

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).