The color of your eyes doesn't depend on your shoe size, and your shoe size doesn't depend on the color of your eyes. All the other examples have a clear independent and dependent variable.
There are 6 sides on a die, so there are 6 numbers: 1, 2, 3 ,4 ,5 and 6. The probability of rolling a 6 would be 1 out of 6 numbers which is written as 1/6.