Fission takes place when an animal divides into two parts, and if the nucleus breaks up into lighter elements, it is called fission . Given these facts, what breaks up into two lighter elements when an animal divides into two parts among the following options:
- the blood cells
 - the heart
 - Energy.
 - the main element
 - heat energy
 - light energy
 - the nucleus
 - sensory neurons


 

       the nucleus  