Abird is placed in a chamber with two pecking keys. the green one provides food on a vi60 sec (variable interval of 60 seconds) schedule and the yellow key provides food on a vi180 sec schedule. according to the matching law, what is the percentage of time the bird pecks the green key?

What belongs in the areas marked x and y? x: the internal energy of a piston system increases as heat is added and rises to a cool area y: as thermal energy is added to a container, some of the energy is lost to the environment x: as thermal energy is added to a container, some of the energy is lost to the environment y: the internal energy of a piston system increases as heat is added and rises to a cool area x: a cold spoon placed in hot liquid gets warmer y: thermal energy is converted to light energy x: thermal energy is converted to light energy y: a cold spoon placed in hot liquid gets warmer