Human system are made of various organs which in turn are made up of various tissues which in turn are made up of various cells. Cells are therefore much more numerous than systems.
As already mentioned, organs are made up of tissues which are made up of cells so statement 4 is right.
As systems are made up of various organs working together, they are more complex than the individual organs. For instance, the Muscular system is more complex than the triceps or bicep muscles.
