Evolution is likely to occur because of i. the potential for a species' population to increase. ii. genetic differences in offspring. iii. a limited supply of necessary resources. iv. selection of offspring that are best able to survive.

Ll. genetic differences in offspring. 
because their are different types of offspring and they make another offspring .
self explanatory 
 

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.