Cell nucleus chromosome gene nucleotide base subunit atom
The correct answer is:
It occurs when part of a chromosome breaks off and attaches to another chromosome.
It results in the duplication of these genes on the same chromosome.
Fragile X syndrome can occur where a person would have 700 insertion repeats.
Difficulties include delay in crawling or walking, hyperactive or impulsive behavior, mental retrdation, flat feet, flexible joints, and large body size.
Hope it helps!