Correct Answer: B

Rationale: The correct answer is B, Femur. The femur is the longest and strongest bone in the human body, located in the thigh region. Long bones are characterized by their elongated shape, such as the femur, which provides support, strength, and mobility. Choices A, C, and D are incorrect because carpal bones (A) are short bones found in the wrist, tarsal bones (C) are short bones found in the ankle, and metacarpal bones (D) are classified as long bones, but they are shorter than the femur and mainly found in the hand.

Correct Answer: A

Rationale: Hydroxyapatite is a mineral compound composed of calcium and phosphorus that plays a crucial role in strengthening the collagen matrix of bones, contributing to their structural integrity and hardness. It is a key component of bone tissue and provides the mineralization necessary for bone strength and density. Choice B is incorrect because the structural unit of a bone is the osteon or Haversian system, not hydroxyapatite. Choice C is incorrect as it describes cartilage, not hydroxyapatite. Choice D is incorrect as it refers to the epiphysis, which is not synonymous with hydroxyapatite.

Correct Answer: D

Rationale: The correct answer is D, 'All of the above.' When viewed from an anterior perspective, the left common carotid artery, pulmonary trunk, and subclavian arteries all carry blood away from the heart. The left common carotid artery supplies oxygenated blood to the head and neck, the pulmonary trunk carries deoxygenated blood to the lungs for oxygenation, and the subclavian arteries transport blood to the upper extremities. Therefore, all the vessels listed in the choices are correct as they function to carry blood away from the heart when viewed anteriorly.

Correct Answer: C

Rationale: The correct answer is C: Chromosome. A chromosome is a structure composed of DNA and proteins that carries genetic information. It is the condensed form of DNA associated with structural proteins, not just a molecule of DNA or protein. Lysosomes are membrane-bound organelles containing digestive enzymes, not DNA and protein. Centrosomes are involved in cell division, not related to DNA and protein together. A genome refers to an organism's complete set of DNA, not specifically a molecule containing both DNA and structural protein.

Correct Answer: B

Rationale: The correct answer is B, Femur. The femur is the longest and strongest bone in the human body, located in the thigh region. Long bones are characterized by their elongated shape, such as the femur, which provides support, strength, and mobility. Choices A, C, and D are incorrect because carpal bones (A) are short bones found in the wrist, tarsal bones (C) are short bones found in the ankle, and metacarpal bones (D) are classified as long bones, but they are shorter than the femur and mainly found in the hand.