Nokea
Which hormone, produced by the adrenal glands, prepares the body for a 'fight or flight' response by increasing heart rate, dilating airways, and mobilizing energy stores?
- A. Cortisol
- B. Aldosterone
- C. Epinephrine
- D. Insulin
Correct Answer: C
Rationale: Epinephrine, also known as adrenaline, is the hormone produced by the adrenal glands that prepares the body for a 'fight or flight' response. It increases heart rate, dilates airways, and mobilizes energy stores to provide the body with the necessary resources to respond to a perceived threat or stressor. Cortisol, although produced by the adrenal glands, is not responsible for the 'fight or flight' response; it is involved in regulating metabolism, immune response, and stress. Aldosterone, another hormone produced by the adrenal glands, primarily regulates electrolyte and fluid balance. Insulin, produced by the pancreas, is responsible for regulating blood sugar levels and is not directly involved in the 'fight or flight' response.
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How does the mass of an object affect its inertia?
- A. Mass has no impact on inertia
- B. Higher mass increases inertia
- C. Higher mass decreases inertia
- D. Mass influences gravitational force, not inertia
Correct Answer: B
Rationale: Inertia is the resistance of an object to changes in its state of motion. The greater the mass of an object, the greater its inertia because it requires more force to change its state of motion. This concept aligns with Newton's first law of motion, which states that an object at rest will remain at rest, and an object in motion will continue in motion with the same speed and direction unless acted upon by an external force. Therefore, higher mass increases inertia, making it more difficult to alter the object's state of motion. Choice A is incorrect as mass does impact inertia. Choice C is incorrect as higher mass actually increases inertia, not decreases it. Choice D is incorrect as while mass does affect gravitational force, it also directly impacts inertia.
Balance the following redox reaction in acidic solution: Iâ» (aq) + Crâ‚‚O₇²â» (aq) -> Iâ‚‚ (aq) + Cr³âº (aq). Identify the oxidizing agent and reducing agent.
- A. Iâ» is oxidized, Crâ‚‚O₇²â» is reduced
- B. Iâ» is reduced, Crâ‚‚O₇²â» is oxidized
- C. Both Iâ» and Crâ‚‚O₇²â» are oxidized
- D. Both Iâ» and Crâ‚‚O₇²â» are reduced
Correct Answer: B
Rationale: In the given redox reaction, Iâ» is gaining electrons to form Iâ‚‚, which means Iâ» is being reduced (undergoing reduction). On the other hand, Crâ‚‚O₇²â» is losing electrons to form Cr³âº, indicating that Crâ‚‚O₇²â» is being oxidized (undergoing oxidation). Therefore, Iâ» is the reducing agent and Crâ‚‚O₇²â» is the oxidizing agent. Choice A is incorrect because Iâ» is being reduced, not oxidized. Choice C is incorrect as both species cannot be oxidized in the same reaction. Choice D is incorrect as both species cannot be reduced in the same reaction.
Which part of the brainstem is responsible for controlling vital functions such as heart rate, blood pressure, and breathing?
- A. Medulla oblongata
- B. Pons
- C. Midbrain
- D. Cerebellum
Correct Answer: A
Rationale: The medulla oblongata is the correct answer. It is responsible for controlling vital functions such as heart rate, blood pressure, and breathing. This part of the brainstem contains centers that regulate these essential autonomic functions to maintain homeostasis in the body. The pons and midbrain are also parts of the brainstem, but they are not primarily responsible for controlling these vital functions. The cerebellum, on the other hand, is involved in coordination and balance, not in regulating vital functions like heart rate, blood pressure, and breathing.
What is the main purpose of biological classification?
- A. To create a rigid and unchanging system for labeling organisms
- B. To understand the diversity and interconnectedness of life
- C. To simplify nature into neat and tidy categories
- D. To assign organisms to specific ecological niches
Correct Answer: B
Rationale: Biological classification, also known as taxonomy, is the science of categorizing and organizing living organisms based on shared characteristics. The main purpose of biological classification is not to create a rigid and unchanging system (option A) or to simplify nature into neat and tidy categories (option C). Instead, it aims to help us understand the diversity of life on Earth and how different organisms are related to each other. By classifying organisms into groups based on their evolutionary relationships, we can gain insights into the interconnectedness of life and better appreciate the complexity and beauty of the natural world. Assigning organisms to specific ecological niches (option D) is more related to ecological studies rather than biological classification.
What property of a substance remains constant regardless of changes in its location in the universe?
- A. Mass
- B. Weight
- C. Density
- D. Volume
Correct Answer: A
Rationale: Mass is the amount of matter in an object and remains constant regardless of its location in the universe. Weight, on the other hand, is the force of gravity acting on an object and can vary depending on the gravitational pull at different locations. Density and volume can change based on the conditions the substance is in, so they are not constant properties. Therefore, the correct answer is mass as it does not change with changes in location.