Final answer:
The majority of chromosome inversions do not cause phenotypic changes because they do not alter the total amount of genetic material, simply rearrange the gene orientation without disrupting genetic sequences.
Step-by-step explanation:
The great majority of inversions do not cause phenotypic consequences because the total amount of genetic material does not change in a given chromosome. Inversions may involve the detachment, 180° rotation, and reinsertion of a chromosome segment, which unless they disrupt a gene sequence, only change the orientation of genes. Such changes are typically milder compared to those caused by deletions or duplications of genetic material. During reproduction, however, they may cause issues by altering gene alignment during meiotic pairing, potentially leading to infertility.