Matching chromosome structures to their functions

Steps:

• Define centromere as the region binding sister chromatids and attaching to spindle fibers during mitosis.
• Define chromatid as a replicated chromosome arm consisting of double-stranded DNA wrapped around histone proteins.
• Define telomere as repetitive DNA sequences at chromosome ends that protect against shortening and degradation.
• Compare definitions to options, identifying A as the only match for all three structures.

Why A is correct:

• Centromere binds sister chromatids (per mitosis definition), chromatids contain histone-bound double-stranded DNA (per chromatin structure), and telomeres prevent end shortening (per telomere function in replication).

Why the others are wrong:

• B: Chromatids are double-stranded with histones, not single-stranded; telomeres protect ends, not just nearest genes.
• C: Centromeres do not produce DNA; telomeres contain repetitive sequences, not undefined "based on."
• D: Centromeres split at anaphase, not metaphase; chromatids are double-stranded with histones, not single-stranded.

Final answer: A