Correct Answer: D

Rationale: Binary fission is the correct answer for bacterial replication because it is the process by which bacteria divide into two identical daughter cells. During binary fission, the bacterial cell replicates its DNA, forms a septum dividing the cell into two, and eventually splits into two daughter cells. This process is specific to prokaryotic cells such as bacteria and is different from mitosis and meiosis, which are processes specific to eukaryotic cells. Cytokinesis is the final step of cell division in both eukaryotes and prokaryotes, but it is not the primary mechanism of bacterial replication.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Mycobacterium leprae is the correct answer because it is the bacterium responsible for causing leprosy. 2. Neisseria gonorrhoeae causes gonorrhea, not leprosy. 3. Escherichia coli is associated with gastrointestinal infections, not leprosy. 4. Staphylococcus aureus causes various skin infections, but not leprosy. In summary, Mycobacterium leprae is the correct choice because it is the specific bacterium known to cause leprosy, while the other options are associated with different diseases.

Correct Answer: D

Rationale: The correct answer is D because HIV can be transmitted from a mother to a child through multiple modes: during delivery through mixing of blood, during pregnancy through the placenta, and via breastmilk during lactation. Each mode presents a risk of transmission due to the presence of the virus in bodily fluids. Therefore, all of the above options are preferred modes of transmission for HIV from a mother to a child. Choices A, B, and C alone do not fully encompass all the possible routes of transmission, making them incorrect.

Correct Answer: A

Rationale: Step 1: The soil is low-contaminated according to the sanitary indicative value, which indicates that the contamination is recent. Step 2: The soil is contaminated according to coli titer, suggesting the presence of coliform bacteria typically found in fresh fecal matter. Step 3: The soil is low-contaminated according to the anaerobe titer (Cl. perfringens), which is an indicator of recent fecal contamination. Step 4: Based on the above steps, the correct answer is A: Fresh fecal contamination, as the presence of coliform bacteria and recent anaerobe titer levels point to recent fecal contamination. Summary: B: Old fecal contamination - Incorrect because the indicators suggest recent contamination. C: Insufficient intensity of soil humification - Incorrect as it is not related to the specific indicators mentioned in the question. D: Constant entry of organic protein contaminations - Incorrect as the indicators point towards fecal contamination, not protein

Correct Answer: D

Rationale: The correct answer is D: Imipenem. Imipenem is a carbapenem antibiotic effective against multiple-resistant microorganisms due to its broad spectrum and resistance to beta-lactamases. It is often used as a last resort for severe infections. Ampicillin (A) and Penicillin (B) are both beta-lactam antibiotics that are less effective against multiple-resistant microorganisms due to widespread resistance mechanisms. Augmentin (C) is a combination of amoxicillin and clavulanic acid, which may have limited efficacy against certain resistant strains but is not as effective as imipenem for treating infections caused by multiple-resistant microorganisms.