Which of the following is an example of aseptic technique?
- A. Washing hands with soap and water before surgery
- B. Coughing into your elbow
- C. Sharing a stethoscope without cleaning
- D. Leaving a wound dressing exposed
Correct Answer: A
Rationale: Aseptic technique refers to practices that help prevent the introduction of harmful microorganisms into a sterile environment. Washing hands with soap and water before surgery is an essential component of aseptic technique as it helps reduce the number of microorganisms on the hands, decreasing the risk of introducing pathogens into the surgical site. Coughing into your elbow is a good hygiene practice to prevent the spread of respiratory infections but is not specifically related to aseptic technique. Sharing a stethoscope without cleaning can introduce microorganisms from one patient to another, compromising aseptic conditions. Leaving a wound dressing exposed can lead to contamination and infection, which is contrary to aseptic technique.
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Which biome is characterized by cold temperatures, permafrost, and coniferous trees?
- A. Tundra
- B. Desert
- C. Rainforest
- D. Savanna
Correct Answer: A
Rationale: A) Tundra: This biome is characterized by cold temperatures, permafrost (permanently frozen subsoil), and vegetation such as mosses, lichens, and coniferous trees like spruce and fir. The tundra is found in high latitudes near the Arctic Circle and high altitudes in mountainous regions. It is a cold and harsh environment where the ground remains frozen for a significant part of the year. The coniferous trees in this biome are adapted to survive in extreme cold conditions.
B) Desert: Deserts are characterized by low precipitation levels and high temperatures, with sparse vegetation adapted to arid conditions.
C) Rainforest: Rainforests are characterized by high levels of rainfall, warm temperatures, and dense vegetation with a variety of plant and animal species.
D) Savanna: Savannas are tropical grasslands with scattered trees and shrubs, characterized by a distinct wet and dry season. They have a different climate pattern compared to the cold temperatures and permafrost found in the tundra biome.
In this case, the description of cold temperatures, permafrost, and coniferous trees aligns most closely with the characteristics of the tundra biome, making option A the correct answer.
What is the main difference between a nuclear reactor and a nuclear bomb?
- A. Reactors use enriched uranium, while bombs use natural uranium.
- B. Reactors have controlled chain reactions, while bombs have uncontrolled chain reactions.
- C. Reactors generate electricity, while bombs cause explosions.
- D. Reactors use moderators, while bombs don't.
Correct Answer: B
Rationale: The main difference between a nuclear reactor and a nuclear bomb is that reactors have controlled chain reactions, while bombs have uncontrolled chain reactions. Nuclear reactors are designed to sustain a controlled nuclear reaction to generate electricity. In contrast, nuclear bombs are designed to release a massive amount of energy in an uncontrolled chain reaction, resulting in an explosion. Choice A is incorrect because both reactors and bombs can use enriched uranium. Choice C is incorrect as nuclear reactors also generate electricity, not just bombs. Choice D is incorrect because both reactors and bombs may or may not use moderators, but the key distinction lies in the control of the chain reaction.
Which of the following is NOT a common route of transmission for a sexually transmitted infection (STI)?
- A. Unprotected sexual contact
- B. Sharing contaminated needles
- C. Deep kissing
- D. Mother to child during childbirth
Correct Answer: C
Rationale: A) Unprotected sexual contact is a common route of transmission for sexually transmitted infections (STIs) as many STIs are spread through genital, anal, or oral sex without the use of barrier protection such as condoms. B) Sharing contaminated needles can also transmit STIs such as HIV and hepatitis B and C, especially among individuals who inject drugs. C) Deep kissing, while it can transmit certain infections like herpes simplex virus (HSV-1) or cytomegalovirus (CMV), is not a common route of transmission for most STIs. Although some STIs can be transmitted through saliva, deep kissing is not a primary mode of transmission for most STIs. D) Mother to child transmission during childbirth can occur with certain STIs such as HIV, syphilis, and herpes, where the infection can be passed from the mother to the baby during delivery. Therefore, deep kissing (option C) is the correct answer as it is not a typical route of transmission for most STIs.
Homologous structures are similar structures in different organisms that have a common evolutionary origin. An example is:
- A. Butterfly wings and bird wings (analogous structures with different origins)
- B. The arm of a human, the wing of a bat, and the flipper of a whale
- C. The eyes of an octopus and a human (convergent evolution with different origins)
- D. The stinger of a bee and the barb of a cactus (unrelated structures)
Correct Answer: B
Rationale: Homologous structures are similar structures found in different organisms that share a common evolutionary origin. The arm of a human, the wing of a bat, and the flipper of a whale are all examples of homologous structures. Despite serving different functions, they share a common underlying structure due to their evolutionary relationship, evidencing a shared ancestry. These structures are modified over time to suit the specific needs of each species. Option A (Butterfly wings and bird wings) refers to analogous structures with different origins. Option C (The eyes of an octopus and a human) describes convergent evolution where traits evolve independently. Option D (The stinger of a bee and the barb of a cactus) are unrelated structures.
What is the primary function of coronary arteries?
- A. Delivering oxygenated blood throughout the body.
- B. Supplying oxygenated blood to the heart muscle itself.
- C. Carrying deoxygenated blood back to the heart.
- D. Regulating blood pressure through vasoconstriction and vasodilation.
Correct Answer: B
Rationale: The primary function of coronary arteries is to supply oxygenated blood to the heart muscle itself. The heart is a muscle that needs a constant supply of oxygen and nutrients to function properly. Coronary arteries branch off the aorta and specifically deliver oxygenated blood to the heart muscle, ensuring its proper function. Choice A is incorrect because coronary arteries do not deliver blood throughout the entire body but specifically to the heart. Choice C is incorrect as coronary arteries carry oxygenated blood away from the heart. Choice D is incorrect as the primary function of the coronary arteries is not to regulate blood pressure but rather to provide oxygenated blood to the heart muscle.