In the sixteenth century, a father-and-son team, by the name of __________, produced a compound microscope consisting of a simple tube with lenses at each end.

Correct Answer: C

Rationale: The correct answer is C: Janssen. In the 16th century, Hans and Zacharias Janssen were a father-and-son team from the Netherlands who are credited with inventing the compound microscope. They constructed a simple tube with lenses at each end, which allowed for magnification of small objects. Their invention significantly contributed to the development of microscopy. Van Leeuwenhoek is known for his contributions to microscopy but did not invent the compound microscope. Semmelweis is known for his work in handwashing and preventing infection. Hooke made significant contributions to microscopy but did not invent the compound microscope.

Correct Answer: A

Rationale: The correct answer is A: Syphilis. Hutchinson's triad is a classic presentation of congenital syphilis. Barrel-shaped teeth, parenchymatous keratitis, and deafness are hallmark signs. These occur due to infection of the fetus by the spirochete Treponema pallidum. Syphilis can lead to various systemic manifestations, including skeletal abnormalities, skin lesions, and neurological complications. Opisthorchiasis, Toxoplasmosis, and Tuberculosis do not typically present with the specific triad described in the question. Opisthorchiasis is a parasitic infection, Toxoplasmosis is caused by a protozoan, and Tuberculosis is a bacterial infection that primarily affects the lungs.

Correct Answer: B

Rationale: The correct answer is B: Mycobacterium tuberculosis. This bacterium is specifically associated with tuberculosis, a contagious disease that primarily affects the lungs. Mycobacterium leprae (choice A) is associated with leprosy, not tuberculosis. Neisseria gonorrhoeae (choice C) causes gonorrhea, a sexually transmitted infection. Streptococcus pneumoniae (choice D) is known for causing pneumonia, not tuberculosis. Therefore, based on the association with the disease tuberculosis, the correct answer is Mycobacterium tuberculosis.

Correct Answer: A

Rationale: The correct answer is A: Neisseria meningitidis. This bacterium is a Gram-negative diplococcus, oxidase-positive, and fermentative. Neisseria meningitidis is known to cause respiratory infections and is commonly found in sputum cultures of patients with such infections. Neisseria gonorrhoeae (B) is also a Gram-negative diplococcus but is not fermentative. Moraxella catarrhalis (C) is oxidase-positive but not fermentative. Haemophilus influenzae (D) is not a diplococcus and is not fermentative. Therefore, Neisseria meningitidis is the most likely causative agent based on the given characteristics.

Correct Answer: A

Rationale: The correct answer is A: Francisella tularensis. This bacterium is classified as a class A bioterrorism agent due to its high virulence and potential for mass casualties. It can cause tularemia, a severe and potentially fatal disease. The other choices, Hepatitis B, E. coli, and Bacillus subtilis, are not considered class A bioterrorism agents. Hepatitis B is a virus causing liver inflammation, E. coli is a common bacterium found in the gut, and Bacillus subtilis is a beneficial bacterium used in various industries. Therefore, Francisella tularensis is the correct choice based on its high pathogenicity and bioterrorism potential.