when an animal moves , chemical energy is converted to mechanical energy & a person is a kind of animal ->  when a person moves, chemical energy is converted to mechanical energy  shaking is a kind of moving & shivering is a kind of shaking ->  shivering is a kind of moving  shivering is a kind of moving & a person shivers ->  the person moves when he is shivering  when a person moves, chemical energy is converted to mechanical energy & the person moves when he is shivering -> when a person shivers, chemical energy is converted to mechanical energy