What is the primary function of red blood cells?
- A. To transport nutrients
- B. To transport oxygen
- C. To fight infection
- D. To produce antibodies
Correct Answer: B
Rationale: The correct answer is B: To transport oxygen. Red blood cells play a crucial role in carrying oxygen from the lungs to all the tissues and organs in the body. This oxygen transport is essential for cellular respiration, where oxygen is used in the production of energy. Red blood cells do not primarily transport nutrients, fight infection, or produce antibodies. Choice A is incorrect because while red blood cells do carry some nutrients, their primary function is to transport oxygen. Choice C is incorrect because immune cells, not red blood cells, are responsible for fighting infections. Choice D is incorrect as antibody production is mainly carried out by specialized white blood cells, not red blood cells.
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What is the basic structural and functional unit of the nervous system?
- A. Axon
- B. Neuron
- C. Dendrite
- D. Synapse
Correct Answer: B
Rationale: The correct answer is B: Neuron. Neurons are indeed the basic structural and functional units of the nervous system. Neurons are specialized cells that transmit signals throughout the nervous system, enabling communication and coordination of various functions within the body. While axons, dendrites, and synapses are all essential components of neurons and neural function, the neuron as a whole is considered the fundamental building block responsible for signal transmission. Choice A, Axon, is incorrect because an axon is a part of a neuron responsible for transmitting electrical signals away from the cell body. Choice C, Dendrite, is incorrect because dendrites are extensions of a neuron that receive signals from other neurons. Choice D, Synapse, is incorrect because a synapse is the junction between two neurons where signals are transmitted.
Which type of muscle is responsible for voluntary movements?
- A. Smooth
- B. Skeletal
- C. Cardiac
- D. Involuntary
Correct Answer: B
Rationale: The corrected question is asking about the type of muscle responsible for voluntary movements, which is skeletal muscle (Choice B). Skeletal muscle is under conscious control and is responsible for voluntary movements like walking or lifting objects. Smooth muscle (Choice A) is found in organs like the intestines and blood vessels, responsible for involuntary movements. Cardiac muscle (Choice C) is specific to the heart and is also involuntary. 'Involuntary' (Choice D) is a general term and does not specify a type of muscle responsible for voluntary movements.
The spleen, a large lymphatic organ, is located in the:
- A. Chest
- B. Abdomen
- C. Pelvis
- D. Head and neck
Correct Answer: B
Rationale: The spleen is located in the abdomen, specifically in the upper left part of the abdomen, under the ribcage and above the stomach. It is an important organ in the lymphatic system responsible for filtering blood, storing blood cells, and fighting infection. It is not located in the chest, pelvis, or head and neck regions. Therefore, the correct answer is 'B: Abdomen.' Choices 'A: Chest,' 'C: Pelvis,' and 'D: Head and neck' are incorrect as the spleen is not situated in these anatomical areas.
Which of the following is a property of amphiprotic substances?
- A. React with acids only
- B. React with bases only
- C. Can act as both acids and bases
- D. Are inert in chemical reactions
Correct Answer: C
Rationale: The correct answer is C: Can act as both acids and bases. Amphiprotic substances have the ability to donate a proton (act as an acid) or accept a proton (act as a base) depending on the reaction conditions. This dual nature allows them to participate in a wide range of chemical reactions, making them versatile and important in various chemical processes. Choices A and B are incorrect because amphiprotic substances are not limited to reacting with only acids or bases; they can interact with both. Choice D is incorrect because amphiprotic substances are not inert; they actively participate in chemical reactions by donating or accepting protons.
Which hormone is responsible for regulating blood sugar levels?
- A. Thyroxine
- B. Insulin
- C. Adrenaline
- D. Cortisol
Correct Answer: B
Rationale: The correct answer is B: Insulin. Insulin, produced by the pancreas, plays a crucial role in regulating blood sugar levels by facilitating glucose uptake into cells. Thyroxine, adrenaline, and cortisol do not directly regulate blood sugar levels. Thyroxine is produced by the thyroid gland and regulates metabolism. Adrenaline and cortisol are hormones involved in stress responses and do not have a primary function in blood sugar regulation. Understanding the functions of these hormones is crucial in differentiating their roles in the body and identifying the specific hormone responsible for blood sugar regulation.
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