solve the Unification problems in prolog given below

Do these开发者_开发问答 terms unify? Why?

1. likes(jax, X). and likes(X, jin).

2. food(X, Y, Z). and food(M, M, M).

3. food(b, c, d(a)). and food(X, X, X).

In below clause, X will instantiate to what value?

4. [X|Y]= [likes(jin, black(dog)),likes(kate, dog)].

I need the answer for the above query and justify the answer.