B. More drastic change than a point mutation
Answer: DNA
Explanation:
A chromosome is a thread-like material with a long structure found in the cell nucleus. It mainly contains DNA and proteins. Due to the presence of DNA in chromosomes, it carries several genes.
The total number of chromosomes in human cell is 46: 44 are non-sex chromosomes while 2 are sex chromosomes
The answer is the nervous system.
Hope this helps!