If a fragment of a chromosome breaks off and then reattaches to the original chromosome but in the reverse direction, the resulting chromosomal abnormality is called

The resulting chromosomal abnormality is called INVERSION

Explanation:

Inversion occurs when a DNA sequence occupying located on the chromosome is broken off, reversed against the native genetic sequence previously present in the genome, and then reattached.

It results in the chromosomal abnormality called inversion.

i don't know, but does anyone wanna be friends? i'm doing my homework at 1: 49 in the morning : /

nucleus

would be most reasonable answer tbh