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 is a non-pathogenic microbe?

Lactobacillus

The correct answer is Option (3) → Lactobacillus

Lactobacillus:

• Lactobacillus is a non-pathogenic bacterium commonly found in the human gut and in fermented foods like yogurt. It is beneficial and plays a role in maintaining a healthy gut microbiome.

 Streptococcus pneumoniae:

• This bacterium is pathogenic and is known to cause diseases such as pneumonia, meningitis, and ear infections.

Haemophilus influenzae:

• This is also a pathogenic bacterium that can cause respiratory infections, pneumonia, meningitis, and other serious illnesses.

Salmonella typhi:

• This bacterium is pathogenic and causes typhoid fever, a serious illness transmitted through contaminated food and water.

Lactobacillus is the non-pathogenic microbe among the options provided, as it is generally beneficial and not associated with causing diseases.