1. Which of the following are valid Java identifiers? If not, why not? a. int1 b. 3months c. _Time1 d. time_2 e. new f. MAX_SIZE g. temp.1 h. tom&jerry i. dateList j. $amount 2. Show how to create an integer variable called age with a value of 21. Then change its value to 35. 3. Show how to create an integer constant for the number of inches in a foot. Can this value be changed? 4. Show how to create a floating point variable called weight with a value of 34.56. 5. Show how to create a character variable called letter set to the third letter in the alphabet.