Marwan Understands That When a Ball of Clay Is Flattened

Multiple Choice

Marwan understands that when a ball of clay is flattened into a pancake shape that there's still the same amount of clay.He says,"you could just bunch up the clay into a ball again-it's still the same thing." He is exhibiting:

A) conservation.
B) identity.
C) reversibility.
D) all of the above