From which of the following germ layers does the nervous system develop?
- A. Ectoderm
- B. Endoderm
- C. Gastroderm
- D. Mesoderm
Correct Answer: A
Rationale: The correct answer is A: Ectoderm. The nervous system develops from the ectoderm, which is the outermost of the three germ layers. The ectoderm gives rise to structures such as the skin, hair, nails, and the entire nervous system. Choices B, C, and D are incorrect because the endoderm gives rise to the lining of the gut and associated organs, the gastroderm is not a recognized germ layer, and the mesoderm forms structures like muscles, bones, blood, and the circulatory system, but not the nervous system.
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What is the name of the long bone found in the upper arm?
- A. Femur
- B. Tibia
- C. Humerus
- D. Radius
Correct Answer: C
Rationale: The correct answer is the humerus. The humerus is the long bone located in the upper arm, between the shoulder and elbow. Option A, Femur, is incorrect as it is the long bone found in the thigh. Option B, Tibia, is incorrect as it is a long bone found in the lower leg. Option D, Radius, is incorrect as it is a bone located in the forearm, not the upper arm.
Which element is essential for the formation of hemoglobin?
- A. Calcium
- B. Iron
- C. Potassium
- D. Sodium
Correct Answer: B
Rationale: The correct answer is Iron. Iron is essential for the formation of hemoglobin, the protein in red blood cells that binds and transports oxygen throughout the body. Calcium (Choice A), Potassium (Choice C), and Sodium (Choice D) are not directly involved in the formation of hemoglobin and its oxygen-carrying function.
What is the function of the Vas Deferens?
- A. Produces fluid to increase sperm mobility
- B. Site where the egg matures
- C. Helps control urine flow
- D. Connects each testis to the urethra
Correct Answer: D
Rationale: The vas deferens is a duct that connects each testis to the urethra, allowing the transport of sperm.
Choice A is incorrect because the vas deferens does not produce fluid to increase sperm mobility.
Choice B is incorrect as the vas deferens is not a site for egg maturation.
Choice C is incorrect as the vas deferens does not help control urine flow, its primary role is in the transport of sperm.
Which blood type is known as the universal donor?
- A. Type A
- B. Type B
- C. Type AB
- D. Type O
Correct Answer: D
Rationale: Type O blood is known as the universal donor because it lacks antigens on the surface of red blood cells. This characteristic makes it compatible with all blood types during transfusions. Type A, Type B, and Type AB blood types have specific antigens that can cause adverse reactions if transfused to an incompatible recipient.
Which part of the brain is responsible for controlling involuntary actions like breathing and heart rate?
- A. Cerebellum
- B. Medulla oblongata
- C. Cerebrum
- D. Thalamus
Correct Answer: B
Rationale: The correct answer is the Medulla oblongata. This region of the brain is located in the brainstem and is responsible for controlling vital autonomic functions such as breathing, heart rate, and blood pressure. The Cerebellum (Choice A) is primarily involved in coordination and balance. The Cerebrum (Choice C) is responsible for higher brain functions like thinking and voluntary muscle movement. The Thalamus (Choice D) acts as a relay station for sensory information but is not primarily responsible for controlling involuntary actions like breathing and heart rate.