Which term refers to the specialized swelling that secretes the cocoon during reproduction in earthworms?

Which term refers to the specialized swelling that secretes the cocoon during reproduction in earthworms?

• A. Reproductive structures
• B. Crop
• C. Clitellum
• D. Posterior

Answer: (C)

The main idea here is the structure in earthworms that forms and secretes the protective cocoon for the eggs. The clitellum is a thick, glandular swelling that appears as a band around the body during sexual maturity. It glands secrete mucus (and later albumin) to create the mucous cocoon. As reproduction proceeds, eggs released from the oviducts are deposited into this cocoon, and sperm received from the other worm are held inside, fertilizing the eggs within the cocoon. The cocoon then slides off the worm, providing a protected environment for development of the embryos. Other terms don’t fit this role: the crop is part of the digestive system, and the posterior simply refers to the tail end, while “reproductive structures” is too general to specify cocoon formation.

The main idea here is the structure in earthworms that forms and secretes the protective cocoon for the eggs. The clitellum is a thick, glandular swelling that appears as a band around the body during sexual maturity. It glands secrete mucus (and later albumin) to create the mucous cocoon. As reproduction proceeds, eggs released from the oviducts are deposited into this cocoon, and sperm received from the other worm are held inside, fertilizing the eggs within the cocoon. The cocoon then slides off the worm, providing a protected environment for development of the embryos.

Other terms don’t fit this role: the crop is part of the digestive system, and the posterior simply refers to the tail end, while “reproductive structures” is too general to specify cocoon formation.