Correct Answer: D

Rationale: Copper is crucial for the formation of red blood cells as it is a component of enzymes involved in the production of hemoglobin. Hemoglobin, the protein in red blood cells responsible for transporting oxygen throughout the body, requires copper for its synthesis. A deficiency in copper can result in anemia due to insufficient production of red blood cells. Selenium, calcium, and magnesium do not play a direct role in red blood cell formation, making them incorrect choices for this question.

Correct Answer: A

Rationale: The corpus callosum is a structure in the brain that enables communication between the two hemispheres. It allows for the transfer of various types of information, such as motor, sensory, and cognitive, between the left and right brain hemispheres, aiding in overall brain function and integration of tasks. Choices B, C, and D are incorrect as they do not involve the specific brain structures connected by the corpus callosum.

Correct Answer: A

Rationale: Beriberi is a disease caused by a deficiency of thiamine, also known as vitamin B1. Thiamine is essential for the proper functioning of the nervous system and energy metabolism in the body. Without enough thiamine, individuals may develop symptoms such as weakness, fatigue, nerve damage, and heart problems, which are characteristic of beriberi. Vitamin C (choice B), niacin (choice C), and protein (choice D) deficiencies can cause other health issues but are not directly related to beriberi.

Correct Answer: C

Rationale: The correct answer is C: lymphatic system. The spleen is a vital organ in the lymphatic system, responsible for filtering blood, producing and storing white blood cells, and aiding the body in fighting infections. The lymphatic system is crucial for maintaining the body's immune defenses and fluid balance. Choices A, B, and D are incorrect because the spleen is not part of the nervous system, integumentary system, or urinary system.

Correct Answer: D

Rationale: The correct answer is D. The endocrine system plays a vital role in the regulation of sexual functions within the reproductive system. It produces hormones that are responsible for various functions, such as the development of secondary sex characteristics, production of gametes (sperm and egg cells), and the regulation of the menstrual cycle. These hormones are crucial for the proper functioning and coordination of the reproductive system, ensuring the successful reproduction and maintenance of reproductive health. Choices A, B, and C are incorrect because the reproductive system is not primarily responsible for transforming minerals into nutrients, determining the sex of the embryo, or controlling the growth of secondary sex organs. These functions are mainly regulated by the endocrine system in coordination with the reproductive system.