The correct answer is: C. Both A & B
An ecosystem is a community of living organisms and the non-living environment with which they interact. The non-living environment includes
the air, water, soil, and sunlight.Autotrophs are organisms that can make their own food. They do this through a process called photosynthesis. Photosynthesis uses sunlight to convert carbon dioxide and water into glucose and oxygen.
Heterotrophs are organisms that cannot make their own food. They must consume other organisms or organic matter to obtain energy.
Both autotrophs and heterotrophs are essential for an ecosystem to function. Autotrophs
produce the oxygen that heterotrophs need to breathe. Heterotrophs consume the organic matter that autotrophs produce.Option A is incorrect because an ecosystem can exist without autotrophs. For example, a hydrothermal vent ecosystem is based on chemosynthetic bacteria that obtain energy from chemical reactions in the Earth’s crust.
Option B is incorrect because an ecosystem can exist without heterotrophs. For example, a hot spring ecosystem is based on autotrophic algae that photosynthesize using the heat from the Earth’s crust.
Option D is incorrect because photosynthesizers are a type of autotroph.