EVERYDAY SCIENCE

Detailed explanation-1: -The majority of bacteria are heterotrophic i.e. can not prepare their own food. Heterotrophic bacteria feed on dead plants and animals, thus they are referred to as decomposers . Heterotrophic bacteria are found in soil, food, and water, and can act as a parasite thereby causing diseases in humans, animals, and plants.

Detailed explanation-2: -Most bacteria are heterotrophic, living off other organisms. Most of these are saprobes, bacteria that live off dead organic matter. The bacteria that cause disease are heterotrophic parasites. There are also many non-disease-causing bacterial parasites, many of which are helpful to their hosts.

Detailed explanation-3: -As we can see from the discussion, most bacteria are heterotrophs while some are photo or chemosynthetic autotrophs. Therefore, the correct answer is option D (Mostly bacteria are heterotrophic but some autotrophic).

Detailed explanation-4: -Heterotrophic bacteria derive energy from organic compounds. They help in nutrient recycling. They decompose dead and decaying plants and animal remnants and help in biodegradation. Heterotrophic bacteria are used for making curd, antibiotics, nitrogen-fixation, etc.

Detailed explanation-5: -Most heterotrophic bacteria are saprophytes, meaning that they obtain their nourishment from dead organic matter. In the soil, saprophytic bacteria and fungi are responsible for biodegradation of organic material.