Question

Assertion:
Chemosynthesis is autotrophic nutrition.

Reason:
Chemoautotrophs contain chlorophyll pigments.

A. Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct, but Reason is not the correct explanation for Assertion.
C. Assertion is correct, but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

Hint: Chemoautotrophs can synthesise their own organic molecules from the fixation of carbon dioxide. These organisms can generate their own source of food, or energy. Chemosynthesis takes place in bacteria and other organisms and includes the use of energy released by inorganic chemical reactions to generate food.

Complete step-by-step answer:
Chemosynthesis is the synthesis of organic compounds with the use of energy acquired through oxidising inorganic compounds. Chemosynthesis takes place in a lack of sunlight, in places such as hydrothermal vents in ocean depths. Organisms living in hydrothermal vents use inorganic compounds emerging from the seabed as their source of energy for the creation of food. Therefore, hydrothermal vents are composed of high biomass which includes the sparse distribution of animals, who rely on food dropping down by chemosynthesis. Chemosynthesis is autotrophic nutrition where organisms (referred to as chemoautotrophs) synthesise organic substances through energy obtained from the chemical nutrients. Chemoautotrophs do not include chlorophyll pigments as they use carbon dioxide​ for carbon and chemical compounds for energy.

Therefore the correct answer is option C.

Note: Chemosynthesis is mostly carried out by microbes, which are on the seafloor forming the microbial mats. Limpets, scale worms, and snails such as the grazers can be found on the mat eating it. Chemoautotrophs use inorganic energy sources to synthesise organic chemicals from carbon dioxide. Chemoautotrophs include sulphur-oxidising bacteria in deep-sea thermal vents, iron-oxidising bacteria in the lava beds, and nitrogen-fixing bacteria in the soil. Cyanobacteria are contained in nitrogen-fixing bacteria that are classified as chemoautotrophs.