The middle piece of mammalian sperm possesses:

Explanation

The middle piece of mammalian sperm plays a crucial role in providing the energy required for sperm motility and the structure necessary for fertilization. It contains both mitochondria and, in some cases, a centriole. Let's go through each option: a. Mitochondria only: This option is incorrect. While mitochondria are indeed present in the middle piece of mammalian sperm, they are not the only structure found there. b. Centriole only: This option is also incorrect. While centrioles play a role in organizing the microtubules of the sperm tail (flagellum), they are not the sole structure in the middle piece. c. Mitochondria and centriole: This option is partially correct. The middle piece of mammalian sperm does indeed contain both mitochondria and, in some cases, a centriole. The mitochondria provide the energy (in the form of ATP) needed for the sperm to swim, while the centriole is responsible for organizing the microtubules in the flagellum, aiding in sperm motility. d. Nucleus and mitochondria: This option is not accurate for the middle piece. The sperm nucleus is typically located in the head of the sperm, not in the middle piece. While the sperm nucleus contains genetic material, it is not found in the middle piece, which is primarily responsible for providing energy and motility to the sperm. Correct answer: The correct answer is (c) Mitochondria and centriole. Summary: The middle piece of mammalian sperm contains both mitochondria and, in some cases, a centriole. The mitochondria provide the necessary energy for sperm motility, and the centriole helps organize the microtubules in the flagellum for efficient movement.