Nokea
Which process involves the body's natural defense against inhaled dust and allergens?
- A. Cellular respiration
- B. Gas exchange
- C. Ciliary action
- D. Bronchoconstriction
Correct Answer: C
Rationale: Ciliary action refers to the process where tiny hair-like structures called cilia in the respiratory tract help to sweep away inhaled dust and allergens, preventing them from entering deeper into the lungs. This is a crucial part of the body's natural defense mechanism against respiratory irritants. Cellular respiration (A) is the process where cells use oxygen to produce energy, not a defense mechanism against inhaled particles. Gas exchange (B) involves the exchange of oxygen and carbon dioxide in the lungs, not specifically targeting inhaled dust and allergens. Bronchoconstriction (D) is the narrowing of the airways in response to irritants or allergens, which can lead to breathing difficulties, but it is not the primary defense mechanism against these particles.
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What is the recommended daily fluid intake for adults?
- A. 1 liter
- B. 2 liters
- C. 3 liters
- D. 4 liters
Correct Answer: B
Rationale: The recommended daily fluid intake for adults is typically around 2 liters, which is equivalent to about 8 cups or half a gallon. This amount can vary depending on factors such as age, gender, weight, activity level, and climate. Staying adequately hydrated is essential for overall health and helps maintain proper bodily functions, such as regulating body temperature, aiding digestion, and transporting nutrients and oxygen throughout the body. Drinking enough fluids also helps prevent dehydration, which can lead to symptoms like fatigue, headaches, and dizziness. Choice A, 1 liter, is insufficient and may not meet the body's hydration needs, while choices C and D, 3 liters and 4 liters, respectively, are excessive for most adults and could potentially lead to overhydration, which may have negative health consequences. It's important to note that individual fluid needs may vary, so it's always best to consult with a healthcare provider for personalized recommendations.
An object is thrown at an angle. Which of the following forces acts HORIZONTALLY on the object during its flight?
- A. Gravitational force
- B. Normal force from the ground
- C. Air resistance
- D. The force of throwing
Correct Answer: C
Rationale: During the flight of the object, the only force that acts horizontally on the object is air resistance. Air resistance opposes the motion of the object through the air and acts in the direction opposite to the object's velocity. Gravitational force acts vertically downward, influencing the object's weight and vertical motion. The normal force from the ground acts perpendicular to the ground to support the object's weight. The force of throwing initially imparts velocity to the object at an angle, but it does not act horizontally throughout the flight.
How does lymph move through the lymphatic vessels?
- A. By the pumping action of the heart
- B. Due to muscle contractions and breathing movements
- C. Through one-way valves within the vessels
- D. All of the above
Correct Answer: C
Rationale: Lymph moves through the lymphatic vessels due to the presence of one-way valves within the vessels. These valves prevent the backflow of lymph and help propel the fluid forward as muscles contract and relax or due to breathing movements. Unlike blood circulation, the lymphatic system does not rely on the pumping action of the heart to move lymph. Choice A is incorrect because lymphatic circulation does not depend on the pumping action of the heart. Choice B is partly correct as muscle contractions and breathing movements do assist in propelling lymph, but the primary mechanism is the presence of one-way valves within the vessels, making choice C the most accurate answer. Choice D is incorrect as not all options listed contribute to how lymph moves through the lymphatic vessels.
What is the name of the regulatory region in a gene that controls its expression?
- A. Exon
- B. Intron
- C. Promoter
- D. Enhancer
Correct Answer: C
Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression.
B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression.
C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression.
D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter.
Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.
How is power related to work and time?
- A. Power = Work · Time
- B. Power = Work Time
- C. Power = Work + Time
- D. Power = Work - Time
Correct Answer: A
Rationale: Power is defined as the rate at which work is done or the amount of work done per unit of time. The correct formula to relate power, work, and time is Power = Work · Time. This formula shows that power is calculated by dividing the amount of work done by the time taken to do that work, indicating the rate at which work is being done. Choice B (Power = Work Time) is incorrect because multiplying work and time does not yield a measure of power. Choice C (Power = Work + Time) is incorrect as adding work and time does not define power. Choice D (Power = Work - Time) is also incorrect because subtracting work and time does not relate to the concept of power.