SSIS Variables vs Parameters (SSIS Denali)

Question

1. What is the difference between Variables and Parameters in SSIS Denali?
2. If there is any difference then What is that which Variables cannot do that Parameter

Answer 1

The variables & parameters are similar to that are in java, we pass/through some values to certain method/task in the form of parameters and we use them in that particular task we cant change those values since they are external things for that method similarly in SSIS the Project Parameters are used to set certain variables or connections dynamically in the package. where as variables are limited internal to the package level.