Final answer:
Ideograms are illustrations that show chromosome arm and major regions.
Step-by-step explanation:
Illustrations that show chromosome arm and major regions are called ideograms. These ideograms include information such as the length, banding pattern, and centromere position of the chromosomes. Cytologists create karyotypes by photographing and arranging the chromosomes into a chart or karyogram, which is also known as an ideogram.