AP BIOLOGY

Detailed explanation-1: -The Sun is the major source of energy for organisms and the ecosystems of which they are a part. Producers, such as plants and algae, use energy from sunlight to make food energy by combining carbon dioxide and water to form organic matter. This process begins the flow of energy through almost all food webs.

Detailed explanation-2: -Most organisms either directly or indirectly use energy from the sun to survive, but not all of them. Plants and some microbes use the energy from the sun to perform photosynthesis. In photosynthesis, light energy is used to combine CO2 in the air with water to make sugars and oxygen.

Detailed explanation-3: -Autotrophs. Autotrophs are organisms that use energy directly from the sun or from chemical bonds. Commonly called producers, they use energy and simple inorganic compounds to produce organic molecules.

Detailed explanation-4: -The Sun is the only source of energy for all ecosystems on Earth except for deep sea hydro-thermal ecosystem. In deep sea hydro-thermal ecosystem, sunlight cannot penetrate and hence chemical deposits and hydrothermal fluids are the source of energy for the organisms habitat in this ecoystem.

Detailed explanation-5: -Option A Chemosynthetic bacteria do not derive energy directly or indirectly from sun. The source of energy of these bacteria is inorganic substances.