Hair like process on the sperm cell that makes it motile or moveable is

Correct Answer: B

Rationale: The correct answer is B: Flagella. Flagella are whip-like structures that provide motility to sperm cells. They enable the sperm cell to move towards the egg for fertilization. Cilia (choice A) are shorter hair-like structures involved in movement but are not found on sperm cells. Pseudopodia (choice C) are temporary projections used for cell movement in some organisms, not sperm cells. Dendritic processes (choice D) refer to branching extensions of nerve cells, not involved in sperm motility. Therefore, flagella is the most appropriate choice for the hair-like process on the sperm cell that makes it motile.

Correct Answer: B

Rationale: The correct answer is B: Sternum. The sternum is commonly referred to as the breastbone because it is a flat bone located in the center of the chest. It connects to the rib cage and helps protect vital organs such as the heart and lungs. The xiphoid process (choice A) is the lower part of the sternum, the clavicle (choice C) is the collarbone, and the coracoid process (choice D) is a projection on the scapula. Therefore, the sternum is the most appropriate term for the breastbone.

Correct Answer: A

Rationale: The correct answer is A: Lumbar vertebrae. The lumbar vertebrae are the largest and strongest of the vertebral column due to their weight-bearing function in supporting the upper body. They have a larger body and thicker structures compared to other vertebrae, providing stability and support. The sacrum, thoracic, and cervical vertebrae are not as large or strong as the lumbar vertebrae, as they have different functions and shapes tailored to their specific roles in the spine.

Correct Answer: D

Rationale: The correct answer is D: epididymis. After being produced in the testes, sperm move into the epididymis for maturation. The epididymis provides the optimal environment for sperm storage and maturation, allowing them to gain motility and fertilization capability. The seminiferous tubes (A) are where sperm are produced, not matured. The penis (B) is the external organ for ejaculation, not maturation. The vas deferens (C) is the tube that carries mature sperm from the epididymis to the urethra, not the site of sperm maturation.

Correct Answer: D

Rationale: The correct answer is D (16 days) because prophase I of spermatocyte phase involves complex processes like chromosome pairing and recombination, which take time. It is a crucial stage in sperm formation. Choices A, B, and C are incorrect as they underestimate the duration required for these intricate cellular events to occur. A shorter timeframe would not allow for proper genetic exchange and segregation, essential for genetic diversity in offspring. Thus, a longer duration like 16 days is necessary for the completion of prophase I in spermatocyte phase.