A human red blood cell loses its nucleus at one stage of its growth A human brain cell always keeps its nucleus Which cell do you think lives longer Why?

Think about the purpose of the nucleus - to retain genetic information, which is used to produce proteins to replace worn out enzymes or similar. A red blood cell can therefore not regenerate itself when damaged, whereas a brain cell can (to an extent - too much damage and even the brain cell will be destroyed). The average lifespan of a red blood cell is 100 days. The average brain cell is with you all your life.
The nucleus is the 'brain' of the cell. It tells the cell what to do.