Target Exam

CUET

Subject

Biology

Chapter

Microbes in Human Welfare

Question:

Read the passage and answer the following.

Microbes are organisms that cannot be seen with the naked eye. They include bacteria, archaea, protists, viruses, prions, and fungi. They account for most of the diversity of life on earth. Far more microbes inhabit a single person's body than there are people on the entire planet. Microbes also dominate in terms of their ability to live and thrive in extreme environments, including clouds, deep-sea volcanoes, springs, ice caps, and animal intestines. Most animals, including humans, exhibit numerous associations with microbes. Our "human microbiome" includes our skin, hair, mouth, and gut.

Which of the following statements are correct about microbes?

(A) All microbes are pathogenic
(B) Microbes can grow at 80°C temperature
(C) Microbes can be present at places where no other life-forms possibly exist
(D) All microbes are microscopic

Choose the correct answer from the options given below:

Options:

(A) and (D) only

(A) and (B), (C) only

(B) and (C), (D) only

(A) and (C), (D) only

Correct Answer:

(B) and (C), (D) only

Explanation:

The correct answer is Option (3) → (B) and (C), (D) only

Besides macroscopic plants and animals, microbes are the major components of biological systems on this earth. Microbes are present everywhere – in soil, water, air, inside our bodies and that of other animals and plants. They are present even at sites where no other life-form could possibly exist– sites such as deep inside the geysers (thermal vents) where the temperature may be as high as 1000C, deep in the soil, under the layers of snow several metres thick, and in highly acidic environments. Microbes are diverse– protozoa, bacteria, fungi and microscopic animal and plant viruses, viroids and also prions that are proteinacious infectious agents. Microbes like bacteria and many fungi can be grown on nutritive media to form colonies that can be seen with the naked eyes. Such cultures are useful in studies on micro-organisms.Microbes cause a large number of diseases in human beings. They also cause diseases in animals and plants. But not all microbes are harmful; several microbes are useful to man in diverse ways.