Which of the following human diseases listed here is caused by bacteria?

Introduction / Context:
Infectious diseases in humans can be caused by different types of pathogens such as bacteria, viruses, fungi, and parasites. Accurately identifying the causative agent helps in choosing appropriate treatment, for example antibiotics for bacterial infections but not for viral diseases. This basic concept is frequently examined in general knowledge and biology questions. The present question asks you to identify which disease among the given options is caused by bacteria.

Given Data / Assumptions:

• Four human diseases are listed: Tuberculosis, Ascariasis, Chickenpox, and Common cold.
• The question asks you to select the one that is bacterial in origin.
• We assume familiarity with common pathogens responsible for major human diseases.

Concept / Approach:
Tuberculosis, commonly called TB, is caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs but can also involve other organs. Ascariasis is caused by Ascaris lumbricoides, a parasitic roundworm (helminth). Chickenpox is caused by the varicella zoster virus, a DNA virus, and is therefore a viral disease. The common cold is usually caused by a group of respiratory viruses, such as rhinoviruses, coronaviruses, and others. Therefore, the only disease in the list that is caused by a bacterium is Tuberculosis.

Step-by-Step Solution:
Step 1: Recall that Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. Step 2: Recognise that Ascariasis is a worm infestation and therefore classified as a parasitic disease. Step 3: Remember that Chickenpox is due to varicella zoster virus, making it a viral disease. Step 4: Note that the common cold is usually caused by various viruses and not by bacteria. Step 5: Conclude that Tuberculosis is the only disease in the given list clearly caused by bacteria.

Verification / Alternative check:
Medical textbooks describe Tuberculosis as a chronic bacterial infection that spreads mainly through droplets when an infected person coughs or sneezes. Standard treatment involves combinations of antibiotics such as isoniazid and rifampicin, confirming its bacterial nature. Ascariasis is discussed in parasitology sections as a helminthic infection. Chickenpox is grouped under viral exanthems of childhood, and the common cold is consistently attributed to respiratory viruses. These sources confirm the classification, leaving Tuberculosis as the correct bacterial disease in this question.

Why Other Options Are Wrong:

• Ascariasis, an intestinal infection caused by a parasitic roundworm: This is caused by a helminth, not by bacteria.
• Chickenpox, an infection caused by a varicella zoster virus: This is a viral disease, often prevented by vaccination.
• Common cold, usually caused by rhinoviruses and other respiratory viruses: The common cold is viral in origin, and routine colds do not need antibiotics.

Common Pitfalls:
Some learners may mistakenly think that most infections are bacterial simply because antibiotics are widely discussed. In reality, many common infections, especially respiratory illnesses like the common cold and chickenpox, are viral and will not respond to antibiotics. Confusing bacterial with parasitic infections is another pitfall. A good strategy is to memorise a few classic examples of bacterial diseases such as Tuberculosis, cholera, typhoid, and to contrast them with well known viral and parasitic diseases.

Final Answer:
The human disease among the options that is caused by bacteria is Tuberculosis (TB), an infectious disease primarily affecting the lungs.