Correct Answer: C

Rationale: The correct answer is C. Osteoporosis is commonly caused by bone loss that occurs with aging, leading to brittle bones. Choice A, poor nutrition in infancy, is not a direct cause of osteoporosis. Choice B, regularly weight-bearing exercise, actually helps in maintaining bone density and strength, reducing the risk of osteoporosis. Choice D, cerebral palsy and associated disorders, is not a common cause of osteoporosis.

Correct Answer: B

Rationale: The correct treatment for patients with hemophilia A is Factor VIII replacement. Hemophilia A is a genetic disorder where there is a deficiency in clotting factor VIII. Therefore, replacing this factor is crucial in managing and preventing bleeding episodes. Choice A, chemotherapy, is not the correct treatment for hemophilia A. Choice C, heparin administration, is not recommended as it can further increase the risk of bleeding in patients with hemophilia. Choice D, bone marrow transplant, is not a standard treatment for hemophilia A.

Correct Answer: C

Rationale: The correct answer is C: Weakness and confusion. Hypoglycemia is characterized by low blood sugar levels, leading to inadequate glucose supply to the brain, resulting in symptoms like weakness and confusion. Choices A, B, and D are incorrect. Rapid, deep breathing is not typically a sign of hypoglycemia but can be seen in other conditions like respiratory issues. Increased urination is more commonly associated with conditions like diabetes mellitus, while high blood pressure is not a typical sign of hypoglycemia.

Correct Answer: B

Rationale: Disseminated intravascular coagulation (DIC) is characterized by simultaneous clotting and bleeding throughout the body. This imbalance in the body's clotting system leads to the formation of blood clots in small blood vessels, which can consume clotting factors and platelets, ultimately leading to excessive bleeding. Choices A, C, and D are incorrect because they do not describe the characteristic feature of DIC, which involves both clotting and bleeding.

Correct Answer: A

Rationale: Renin is the correct answer. When arterial blood pressure decreases, the kidneys release renin, which triggers a series of reactions ultimately leading to an increase in blood pressure and peripheral resistance. Antidiuretic hormone (choice B) is involved in water retention, atrial natriuretic hormone (choice C) promotes sodium excretion and lowers blood pressure, and insulin (choice D) regulates glucose metabolism, not blood pressure.