Answer:
This is due to the fact that chromosome 21 is not fundamental to sustain and keep life going.
Chromosome 21 is the second human chromosome to be entirely sequenced. Chromosome 21 seems to consists of 200 to 300 genes that supply instructions for developing and forming proteins. These proteins undergo a variety of unique roles in the body.
Chromosome 21 is majorly involved in brain development at the frontal lobe and the medulla oblingata.
