NCERT Class 8 Science — Chapter 2: Microorganisms : friend and foe

mcqeasy

Which one of the following human diseases is caused by a protozoan pathogen?

Official previous-year question

Verified 1 Aug 2026.

Options

ATuberculosis
BMalaria
CChickenpox
DTyphoid

Did you get this right?

Solution

The correct option is

Malaria

Explanation

Infectious diseases in humans are classified based on the nature of the causative agent (pathogen). These agents include bacteria, viruses, protozoa, fungi, and helminths. Identifying the specific category of the pathogen is essential for understanding the disease's pathology and treatment.

Option Analysis

Typhoid is incorrect: Typhoid fever is a bacterial disease caused by the bacterium Salmonella typhi. It typically spreads through contaminated food and water.
Tuberculosis is incorrect: Tuberculosis (TB) is a bacterial infection caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs but can spread to other parts of the body.
Malaria is correct: Malaria is caused by a protozoan parasite belonging to the genus Plasmodium (e.g., P. vivax, P. falciparum). The parasite is transmitted to humans through the bite of an infected female Anopheles mosquito.
Chickenpox is incorrect: Chickenpox is a viral disease caused by the Varicella-zoster virus (VZV). It is highly contagious and characterized by a skin rash.

Key Takeaway: Malaria is a vector-borne disease caused by a protozoan parasite, whereas Typhoid and Tuberculosis are bacterial infections, and Chickenpox is a viral infection.

Your note

More from Chapter 2: Microorganisms : friend and foe

With reference to microorganisms, consider the following statements: 1. They are classified into four major groups: bacteria, fungi, protozoa, and algae. 2. They can survive only in moderate climates and die in ice-cold or hot spring environments. 3. Some microorganisms are unicellular, while others are multicellular. Which of the statements given above is/are correct?

medium

Which one of the following characteristics distinguishes viruses from other microorganisms?

easy

Consider the following statements regarding the habitat of microorganisms: 1. They are found in air, water, and soil but not inside the bodies of animals. 2. They can exist freely as well as grow on other organisms. 3. They are capable of surviving in deserts and marshy lands. Which of the statements given above is/are correct?

medium

Consider the following pairs of microorganisms and their classification: 1. Aspergillus : Algae 2. Paramecium : Protozoa 3. Penicillium : Fungi 4. Spirogyra : Bacteria How many of the above pairs are correctly matched?

hard

With reference to the classification of diseases, consider the following statements: 1. Typhoid and Tuberculosis (TB) are bacterial diseases. 2. Polio and Chicken pox are bacterial diseases. 3. Dysentery is caused by a virus. Which of the statements given above is/are correct?

medium

Keep practising Chapter 2: Microorganisms : friend and foe

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The correct option is

Malaria

Explanation

Option Analysis

Typhoid is incorrect: Typhoid fever is a bacterial disease caused by the bacterium Salmonella typhi. It typically spreads through contaminated food and water.
Tuberculosis is incorrect: Tuberculosis (TB) is a bacterial infection caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs but can spread to other parts of the body.
Malaria is correct: Malaria is caused by a protozoan parasite belonging to the genus Plasmodium (e.g., P. vivax, P. falciparum). The parasite is transmitted to humans through the bite of an infected female Anopheles mosquito.
Chickenpox is incorrect: Chickenpox is a viral disease caused by the Varicella-zoster virus (VZV). It is highly contagious and characterized by a skin rash.

Key Takeaway: Malaria is a vector-borne disease caused by a protozoan parasite, whereas Typhoid and Tuberculosis are bacterial infections, and Chickenpox is a viral infection.