Question

Which of the following is the reason behind the autotrophic nature of algae?
A. It can carry out photosynthesis
B. They depend on other animals for nutrition
C. They are insectivores
D. None of these

Answer 1

Hint: Phototropism is the mode of nutrition where organisms make their own food using environmental resources. The organisms that are capable of phototropism are known as autotrophs. In nature, green plants and algae are autotrophs.

Complete answer:
Option (a) is correct. Photosynthesis is the process by which plants make their own food. The chlorophyll pigment of the plants traps solar energy and uses it to convert water and carbon dioxide into glucose. Oxygen is released during the reaction. Algae can undergo the process of photosynthesis and are thus autotrophic in nature.
Option(b) is incorrect. Organisms that depend on animals for nutrition are consumers in the ecosystem. They are heterotrophs and are unable to synthesize their own food, and thus depend on other organisms for food.
Option (c) is incorrect. Insectivorous plants are carnivorous plants. Typical insectivores among plants are pitcher plants and Venus flytraps. These plants use small arthropods as the source of nutrients. They grow on soil that contain nutrients in poor quantities. However, the carnivorous plants too, undergo photosynthesis for deriving their quota of energy.

Hence, the correct answer is option (A).

Additional information:
Algae are a polyphyletic group of organisms. They are eukaryotic and photosynthetic in nature. The cells of algae are not organized into distinct tissues and lack roots, stems and leaves. Many algae are unicellular and microscopic. Multicellular forms of algae are also present. Algae can thrive in freshwater as well as in saltwater. They can survive in extreme conditions of temperature, pressure, oxygen and carbon levels. Reproduction in algae is carried out via sexual. Asexual and vegetative modes. The importance of algae lies in the fact that they are oxygen producing organisms. Algae are also capable of producing biofuels that are an excellent alternative to fossil fuels.

Note: Algae are photosynthetic organisms that are capable of producing their own food using energy from sunlight, water and carbon dioxide. They are polyphyletic, that is algae are not closely related species, but have certain anatomical and morphological similarities with each other. Algae are primarily aquatic, but certain land algae are also known.