What level identifies one unique organism

Aboy jumps into a cold swimming pool and his body tempature goes down hus muscles ,blood vessels

Has regulatory areas for thirst, hunger, body temperature, water balance, and blood pressure

The table above shows five different types of chromosomal abnormalities that can occur during meiosis. they result in either an individual having too many or too few chromosomes in their genome. what is the most likely cause of these chromosomal abnormalities?