$1.$Write a PL$/$SQL block to find out if a year is a leap year. A leap year is divisible by $4,$ but not divisible by $100,$ or it is divisible by $400.$For example, $2000$ and $2004$ are leap years, but $1900$ and $2001$ are not leap years. $($Hint: The function MOD $($n$,$ d$)$ divides n by d and returns the integer remainder from the operation$)2.$Write a PL$/$SQL block to print all odd numbers between $1$ and $10$ using a basic loop$\mathrm{.}3.$Using a FOR loop, print the values $10$ to $1$ in reverse order$\mathrm{.}4.$Create a table called ITEM with one column ItemNum with NUMBER type. Write a PL$/$SQL program to insert values of $1$ to $5$ for ItemNum$\mathrm{.}5.$Input a number with a substitution variable and then print its multiplication table using a WHILE loop$\mathrm{.}6.$Input a month number between $1$ and $12$ and a $4-$digit year, and print number of days in that month. For February $($month $=2),$ check for leap year to display number of days equal to $28$ or $29\mathrm{.}7.$Use a PL$/$SQL block to delete item number $4$ from the ITEM table created in question $4\mathrm{.}8.$Write a PL$/$SQL block to ask a user to input a valid employee Id$.$Retrieve employees name, qualification description, salary and commission. Print name, qualification and sum of salary and commission.