Final answer:
At the tips of the X chromosome in an individual with Martin-Bell syndrome, one would find telomeres, which are structures that protect the chromosome ends from degradation.
Step-by-step explanation:
While microscopically investigating the chromosomes of an individual with Martin-Bell syndrome, at the tips of the X chromosome you would expect to find telomeres. Telomeres are essential structures composed of non-coding, repetitive DNA sequences at the ends of linear chromosomes. Their main function is to protect the chromosomes from degradation and to prevent the loss of coding DNA during cell division. In human chromosomes, telomeres consist of a six base-pair sequence, TTAGGG, which is repeated several hundred times.
The other options, such as centromeres, satellite DNA, and nucleosomes, have different roles. Centromeres are found at the chromosome's central point, and they are critical during cell division, providing an attachment site for spindle fibers. Satellite DNA consists of repetitive sequences found in some sections of chromosomes, while nucleosomes are the basic units of DNA packaging, involving DNA wrapped around a core of histone proteins. However, these are not found at the tips of chromosomes.