Answer:
a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules
I think the answer is a but I am not for sure
Answer:
Combination of one or more columns used to identify particular rows in a relation is a key
Answer: You need a temporary variable to hold the value 3
Explanation:
So, aList[0] is 3 and aList[1] is 19, if it will be as it is you litteraly say to the compiler to change aList[0] to aList[1] at this moment aList[0] is 19 and aList[1] also is 19 and if you try to change aList[1] to aList[0] it will not change its value because they are the same.
You need temp variable to keep one of the values.
