En las lombrices de tierra se puede observar un anillo de mayor tamaño que el resto.¿ como se llama?¿Para qué sirve?

Follow the directions for self-quiz question 8, draw it, by labeling the appropriate structures with these terms, drawing lines or brackets as needed: chromosome (label as replicated or unreplicated), centromere, kinetochore, sister chromatids, nonsister chromatids, homologous pair, homologs, chiasma, sister chromatid, cohesion