The causative agent of tuberculosis is

1. Analyze the question The question asks which type of organism causes tuberculosis (TB).

2. Explain the concept Diseases are grouped by the type of pathogen that causes them:

• Viruses: HIV/AIDS, influenza, measles, polio, COVID-19
• Bacteria: tuberculosis, cholera, typhoid, tetanus, gonorrhoea
• Protozoa: malaria (Plasmodium), amoebic dysentery, sleeping sickness
• Fungi: ringworm, athlete's foot, candidiasis

3. Step-by-step solution

• Tuberculosis is caused by Mycobacterium tuberculosis.
• This organism is a rod-shaped bacterium (a bacillus).
• It spreads through the air in droplets when an infected person coughs or sneezes, and it mainly attacks the lungs.
• Because the pathogen is a bacterium, we can eliminate the other options: • A (virus): wrong, since viruses are not the cause of TB. • C (protozoa): wrong, since protozoa cause malaria, not TB. • D (fungi): wrong, since fungi cause skin infections like ringworm.

4. Answer The causative agent of tuberculosis is bacteria, which is option B.

5. Exam tip Remember the phrase "TB = Bacteria" (Mycobacterium tuberculosis). A handy way to recall bacterial diseases is "TCT": Tuberculosis, Cholera, Typhoid. Also remember that malaria is protozoan, not bacterial, since students often mix these up. TB is treated with antibiotics, which only work on bacteria. The BCG vaccine protects against it.