Please help with #'s 3&4

Tasks 1. Create a function called even.count. The function should take an integer vector as its argument and should output the number of even numbers from the vector. 2. Create a loop to compute the mean of each column in mtcars. Use the apply() function to accomplish the same task. 3. Create a loop that will assign all uppercase and lowercase letters of the alphabet in a vector. The output should be as follows: "A" "a" "B" "" "C" "c"...and so on until "Z" "z" The LETTERS and letters objects will give a vector of uppercase and lowercase letters of the alphabet, respectively. 4. Create a loop to compute the number of unique values in each column of the iris data frame. The data set iris is built into R. Just type iris and you will have access. You should store your results in a vector and display the results