What is magnet made of

In the conservation of mass, mass (which is the same as energy) can never be created or destroyed in the same way oil is formed from the remains of small animals and plants that died and fell to the bottom of the sea and their mass (energy) is conserved as oil.

The scientist was trying to demonstrate that humans can introduce their own biases into an experiment. bias is a prejudice in favor of one thing compared with the another.in this case, the bias is believing that mice with higher intelligence would solve the maze better.  bias in science should be avoided as it is not desirable that research becomes influenced by scientists personal beliefs.