BOTH SURROUND AND PROTECT AN OBJECT.

BOTH ALOW ONLY CERTAIN THINGS TO ENTER

BOTH CONTAIN A LOT OF IMPOTANT INFORMATION

THEY BOTH PROTECT THE NUCLEUS/ COMPUTER.

BOTH CONTROL WHAT HAPPENS

BOTH FILL THE OTHERWISE EMPTY SPACE

BOTH ALLOW SOMETHING THAT NEEDS TO GO SOMEWHERE TO GET THERE

BOTH ARE ATTACHED TO THE ER/ HALLWAY

BOTH POWER THE STRUCTURE

BOTH GET HOLD WASTE

BOTH GET RID OF OLD STUFF

BOTH CREATE HARNESS OUTWRD ENERGY