The United Nations estimates that by the year 2050 more than __________ of the world’s population will live in urban areas.
- A. 35%
- B. 56%
- C. 60%
- D. 69%
Correct Answer: D
Rationale: The correct answer is D (69%). The UN projects that by 2050, around 69% of the world's population will live in urban areas. This is based on current global urbanization trends and population growth rates. Urban areas are experiencing rapid population growth due to factors like rural-to-urban migration and natural population increase. Choices A, B, and C are incorrect because they underestimate the expected urban population growth by 2050. A (35%), B (56%), and C (60%) are too low compared to the projected 69%. Urbanization is a significant global trend, and it is essential to consider the implications of this shift for sustainability, infrastructure development, and resource allocation.
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Infection of several persons without any epidemiological link is
- A. epidemic
- B. sporadic disease
- C. endemic
- D. pandemic
Correct Answer: B
Rationale: The correct answer is B: sporadic disease. Infection of several persons without any epidemiological link is considered sporadic because it occurs in a random and isolated manner, with no clear pattern or connection between cases. It is not classified as an epidemic (A) because it does not involve a sudden increase in the number of cases within a specific population. It is also not endemic (C) as endemic diseases are constantly present in a particular region or population. Lastly, it is not a pandemic (D) which refers to a global outbreak affecting a large number of people across different countries.
A 65-year-old patient with fever and a productive cough had a sputum sample revealing Gram-negative, non-motile, rod-shaped bacteria. What is the most likely causative agent?
- A. Klebsiella pneumoniae
- B. Pseudomonas aeruginosa
- C. Escherichia coli
- D. Haemophilus influenzae
Correct Answer: A
Rationale: The correct answer is A: Klebsiella pneumoniae. This bacterium is commonly associated with pneumonia in elderly patients. Klebsiella pneumoniae is a Gram-negative, non-motile, rod-shaped bacterium that frequently causes pneumonia in individuals with underlying health conditions. It is known for its ability to produce a distinctive mucoid capsule. Pseudomonas aeruginosa (B) is more commonly associated with hospital-acquired infections, particularly in immunocompromised individuals. Escherichia coli (C) is a common cause of urinary tract infections but is less likely in this case due to the symptoms and sputum sample results. Haemophilus influenzae (D) is another common respiratory pathogen, but in this scenario, Klebsiella pneumoniae is the most likely causative agent based on the patient's age, symptoms, and the characteristics of the bacteria described in the sputum sample.
On the territory of a certain region the mass death of rodents was observed. It was assumed that it may be caused by plague agent. What serological reaction should be applied for quick determination of antigen of this epizootic agent?
- A. Precipitation reaction
- B. Agglutination reaction
- C. Reaction of passive hemagglutination
- D. Bordet-Gengou test
Correct Answer: B
Rationale: The correct answer is B: Agglutination reaction. This is the most suitable serological reaction for the quick determination of the antigen of the epizootic agent causing mass rodent deaths. In agglutination reaction, antibodies cause the clumping of antigens, allowing for easy visual detection of the presence of the specific antigen. This is efficient for rapid diagnosis in cases of suspected infectious diseases like plague.
A: Precipitation reaction is more suitable for identifying soluble antigens, not for quick determination of a specific antigen in this scenario.
C: Reaction of passive hemagglutination is used for measuring the presence of antibodies, not antigens.
D: Bordet-Gengou test is a specific test for the identification of Bordetella pertussis bacterium, not suitable for this scenario.
Which toxin is specific for ETEC:
- A. TSST-1
- B. Shiga-like toxin
- C. Erythrogenic toxin
- D. LT enterotoxin
Correct Answer: D
Rationale: The correct answer is D: LT enterotoxin. This toxin is specific for Enterotoxigenic E. coli (ETEC) and is responsible for causing diarrhea by increasing cyclic AMP levels in intestinal cells. TSST-1 (choice A) is produced by Staphylococcus aureus, not ETEC. Shiga-like toxin (choice B) is produced by Shigella and EHEC, not ETEC. Erythrogenic toxin (choice C) is produced by Streptococcus pyogenes, not ETEC. Therefore, the LT enterotoxin is the specific toxin associated with ETEC.
The drug most often used in fighting protozoan infections of the reproductive system is:
- A. ampicillin
- B. tetracycline
- C. ciprofloxacin
- D. metronidazole
Correct Answer: D
Rationale: The correct answer is D: metronidazole. Metronidazole is specifically effective against protozoan infections due to its ability to target and disrupt the DNA of the parasites. It is commonly used to treat infections such as trichomoniasis and giardiasis that affect the reproductive system. Ampicillin (A) and tetracycline (B) are antibiotics that target bacteria, not protozoa. Ciprofloxacin (C) is also an antibiotic that is effective against certain bacterial infections but not protozoan infections. Therefore, metronidazole is the most appropriate choice for fighting protozoan infections of the reproductive system.