What is a high cranial capacity a good indicator of?

Cranial capacity is how much space there is inside the skull. That's a good indicator of how big the brain is...and brain size has something to do with how smart an animal is. 

Mitochondria is the cell organelle that produced the energy that is needed in the body system in form of atp, that is why it is called the power house of the cell. energy is needed by the living organisms to carry out the activities which sustain life.  if the mitochondria is destroyed atp will not be produced. if the mitochondria is destroyed, energy production will stop and the affected living organism will not have the energy to carry out the necessary life processes; this will lead to the death of the organism.