Nokea
What is the primary function of the respiratory system?
- A. To absorb oxygen
- B. To transport nutrients
- C. To produce sound and speech
- D. To regulate blood pressure
Correct Answer: A
Rationale: The primary function of the respiratory system is to absorb oxygen from the air into the bloodstream and expel carbon dioxide from the body. This process is essential for cellular respiration and the production of energy in the body. Option A, 'To absorb oxygen,' aligns with this crucial function, making it the correct choice. Choices B, C, and D are incorrect as they do not represent the primary function of the respiratory system. The respiratory system is not responsible for transporting nutrients (choice B), producing sound and speech (choice C), or regulating blood pressure (choice D).
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Which type of blood vessel carries blood away from the heart?
- A. Veins
- B. Arteries
- C. Capillaries
- D. Nerves
Correct Answer: B
Rationale: Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. They have thick, muscular walls to withstand the high pressure generated by the heart's contractions, ensuring efficient transport of blood throughout the body. Veins, on the other hand, carry deoxygenated blood back to the heart, while capillaries facilitate the exchange of nutrients, oxygen, and waste products between the blood and tissues. Nerves are not involved in the transport of blood.
Which type of blood vessel carries blood back to the heart?
- A. Arteries
- B. Capillaries
- C. Veins
- D. Lymphatic vessels
Correct Answer: C
Rationale: Veins are the blood vessels that carry deoxygenated blood back to the heart, except for the pulmonary veins which carry oxygenated blood from the lungs. Arteries carry oxygenated blood away from the heart. Capillaries facilitate the exchange of nutrients and gases between the blood and tissues but do not specifically carry blood back to the heart. Lymphatic vessels are part of the lymphatic system responsible for immune function and do not directly carry blood back to the heart. Therefore, the correct answer is veins.
Which part of the brain controls involuntary actions such as breathing and heart rate?
- A. Cerebrum
- B. Cerebellum
- C. Medulla oblongata
- D. Hypothalamus
Correct Answer: C
Rationale: The medulla oblongata, located at the base of the brainstem, controls essential involuntary actions such as breathing, heart rate, and blood pressure. It plays a crucial role in maintaining vital functions necessary for survival. The cerebrum is responsible for voluntary actions, conscious thought, and sensory processing, making it an incorrect choice. The cerebellum primarily coordinates movement, balance, and posture, not involuntary actions like breathing and heart rate. The hypothalamus regulates body temperature, thirst, hunger, and controls the endocrine system, but it is not directly responsible for controlling breathing and heart rate.
Which organelle is responsible for generating energy within a cell?
- A. Nucleus
- B. Ribosome
- C. Mitochondria
- D. Golgi apparatus
Correct Answer: C
Rationale: Mitochondria are commonly referred to as the powerhouses of the cell as they are primarily responsible for generating energy through cellular respiration. This process involves converting nutrients into adenosine triphosphate (ATP), which is the main energy currency of the cell. The nucleus is responsible for storing the cell's genetic material, the ribosome is involved in protein synthesis, and the Golgi apparatus is responsible for packaging and distributing molecules produced by the cell; therefore, they are not directly involved in energy generation.
What is the main function of the digestive system?
- A. To break down food and absorb nutrients
- B. To regulate body temperature
- C. To transport nutrients
- D. To produce hormones
Correct Answer: A
Rationale: The main function of the digestive system is to break down food into nutrients through the process of digestion. Once the food is broken down, the nutrients are absorbed into the bloodstream and utilized by the body for various functions. Choice B, regulating body temperature, is incorrect as it is the function of the body's thermoregulatory system, not the digestive system. Choice C, transporting nutrients, is incorrect as the digestive system primarily focuses on breaking down and absorbing nutrients rather than transporting them. Choice D, producing hormones, is also incorrect as hormone production is mainly carried out by endocrine glands and not the digestive system.