Final answer:
The mature spermatozoan has an acrosome next to the nucleus and the head contains 23 chromosomes, so both A and D are correct. The midpiece contains mitochondria, not chromosomes, and the tail is used for motility.
Step-by-step explanation:
The correct answer to the student's question regarding the structure of a mature human spermatozoan is E) both A and D.
A) The acrosome is next to the nucleus in the head of the sperm, containing enzymes that aid in penetrating the egg during fertilization.
D) The head of the sperm contains 23 chromosomes, which is half of the chromosomal complement of a normal body cell, making the sperm a haploid cell ready to combine with the female gamete.
The midpiece of the sperm does not contain chromosomes, but rather is packed with mitochondria which provide the energy (ATP) necessary for the sperm to move its flagellum, or tail. The tail itself does not contain mitochondria; it is the structure that enables motility thanks to the energy produced in the midpiece.
Through a process called spermatogenesis, sperm develops these structures that are critical for their role in fertilization.