Final answer:
A pericentric inversion includes the centromere within the inverted region of a chromosome. The correct answer is option b).
Step-by-step explanation:
By definition, a pericentric inversion includes the centromere within the inverted region of a chromosome. This type of inversion encompasses a segment that spans both arms of the chromosome, and includes the centromere. Unlike paracentric inversions, which occur outside the centromere and only involve one arm of the chromosome.
Pericentric inversions can significantly affect the chromosome because they change the relative lengths of the chromosome arms. Pericentric inversions can occur during the process of nonhomologous recombination, which is an unequal exchange of genetic material between nonhomologous chromosomes.
The chromosomal arms are detached, rotated 180°, and then reinserted, which may result in genetic material being present in a different orientation. Although a pericentric inversion often does not affect the gene sequence itself, it can have significant effects on gene expression and phenotype if it disrupts the positioning of genes relative to their regulatory elements.