Nokea
An uncharged atom has an electron configuration of 1s2 2s2 2p6 3s2 and a mass number of 14. How many protons does it have?
- A. 14
- B. 6
- C. 8
- D. 12
Correct Answer: B
Rationale: The correct answer is B (6 protons). The electron configuration provided corresponds to the element carbon, which has 6 protons. The mass number does not affect the number of protons in an atom, so despite the mass number of 14, the atom still contains 6 protons. Choice A (14) is incorrect because the mass number does not determine the number of protons. Choices C (8) and D (12) are incorrect as they do not match the number of protons in a carbon atom.
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What is the function of the esophagus in the digestive system?
- A. To absorb nutrients
- B. To transport food from the mouth to the stomach
- C. To break down food
- D. To absorb water
Correct Answer: B
Rationale: The esophagus functions to transport food from the mouth to the stomach through a process called peristalsis, which involves a series of muscle contractions that push the food downward along the digestive tract. Absorbing nutrients (Choice A) is typically done in the small intestine, breaking down food (Choice C) is primarily the role of the stomach and small intestine, and absorbing water (Choice D) mainly occurs in the large intestine.
Which type of blood cell is responsible for carrying oxygen?
- A. White blood cell
- B. Red blood cell
- C. Platelet
- D. Plasma
Correct Answer: B
Rationale: The correct answer is B: Red blood cell. Red blood cells, also known as erythrocytes, are responsible for carrying oxygen from the lungs to the body's tissues. They contain hemoglobin, a protein that binds to oxygen and transports it throughout the body. White blood cells (Choice A) are part of the immune system and help fight infections, not involved in carrying oxygen. Platelets (Choice C) are responsible for blood clotting, not oxygen transport. Plasma (Choice D) is the liquid component of blood that carries various substances like nutrients and waste products, but it does not directly carry oxygen.
Which part of the brain is responsible for voluntary muscle movements?
- A. Medulla oblongata
- B. Cerebrum
- C. Hypothalamus
- D. Thalamus
Correct Answer: B
Rationale: The question inquires about the brain region responsible for voluntary muscle movements. The correct answer is the Cerebrum. The cerebrum is the main part of the brain involved in voluntary muscle control and motor coordination. The Medulla oblongata is primarily responsible for regulating vital functions like breathing and heart rate, not voluntary muscle movements. The Hypothalamus plays a role in regulating body temperature, thirst, hunger, and other homeostatic processes. The Thalamus serves as a relay station for sensory information but is not directly responsible for voluntary muscle movements.
Which of the following correctly orders the layers of the epidermis from most superficial to deepest?
- A. S. spinosum, S. basale, S. corneum, S. granulosum, S. lucidum
- B. S. corneum, S. lucidum, S. granulosum, S. spinosum, S. basale
- C. S. corneum, S. spinosum, S. basale, S. granulosum, S. lucidum
- D. S. basale, S. spinosum, S. granulosum, S. lucidum, S. corneum
Correct Answer: B
Rationale: The correct order of the layers of the epidermis from most superficial to deepest is: Stratum corneum, Stratum lucidum, Stratum granulosum, Stratum spinosum, Stratum basale. Choice B, 'S. corneum, S. lucidum, S. granulosum, S. spinosum, S. basale,' provides the accurate layering from the outermost to the innermost layer of the epidermis. Choice A is incorrect as it starts with Stratum spinosum, which is not the most superficial layer. Choice C is incorrect as it places Stratum spinosum before Stratum basale. Choice D is incorrect as it starts with Stratum basale, which is the deepest layer of the epidermis.
Which type of tissue protects the respiratory system's trachea?
- A. Bone
- B. Cartilage
- C. Collagen
- D. Keratin
Correct Answer: B
Rationale: Cartilage is the correct answer as it provides flexible support and protection in the trachea. Cartilage is specifically designed to maintain the trachea's shape and prevent it from collapsing during breathing. Bone is a rigid tissue, not found in the trachea, and would not provide the necessary flexibility for breathing. Collagen is a structural protein but does not offer the same support and flexibility as cartilage in this context. Keratin is a protein that forms structures like hair and nails, and it is not present in the trachea to provide protection.