Final answer:
Repetitive sequences are identical or similar DNA sequences found multiple times on a chromosome, such as telomeres at chromosome ends or duplicated genes along the chromosome.
Step-by-step explanation:
Identical or similar DNA sequences that occur multiple times on a chromosome are called repetitive sequences. A well-known example of this is the telomere region, which consists of noncoding repetitive sequences crucial for protecting the chromosome's coding regions. Another form of repetitive sequences is due to duplication, where a segment of DNA is copied multiple times, which can sometimes result in multiple gene copies within the chromosome.