by using Linux command

Write the commands to accomplish the following: Show the processes/programs taking up the system resources. Stop one of these running processes. Shutdown the virtual machine. Show the output of head and tail on the same text file. Explain the difference between head and tail. Print the command history list. What are environment variables? How to print all environment variables? How to print the contents of a specific environment variable? Display the amount of used and free memory (RAM) in a human readable format