Question

An ‘ecosystem’ is a small unit of;
A. Hydrosphere
B. Biosphere
C. Atmosphere
D. Earth

Answer 1

Hint: Ecology is the branch of biology that deals with the study of interactions between organisms and their environment. The living organisms are affected by the environment in which they live and on the other hand their activities also affect the environment.

Complete answer: The atmosphere is divided into a series of layers or spheres due to variations in temperatures and pressures at various altitudes. These spheres are troposphere, stratosphere, mesosphere, thermosphere and exosphere.
Biosphere is the entire inhabited part of the earth and its atmosphere including the living components. The global environment consists of three main subdivisions:
-The hydrosphere that includes all the water components.
-The lithosphere that comprises the solid components of the earth’s crust.
-The atmosphere formed of the gaseous envelope of the earth.
-The biosphere consists of the lower atmosphere, the land and the ocean.
 An ecosystem is composed of a biological community integrated with its physical environment through the exchange of energy and recycling of nutrients. Ecosystems can be described as self- regulating and self-sustaining units of landscapes, e.g. a pond or a forest. However no ecosystem operates in isolation. Boundaries between one ecosystem and another are indistinct and overlapping and all ecosystems on earth are joined together to form a single global ecosystem known as biosphere. So an ecosystem is a small unit of biosphere.
So, the correct answer is “Option B”.

Note: The term ecosystem was coined by Sir Arthur Tansley in 1935. An ecosystem has two basic components- biotic comprises living organisms and abiotic comprises nonliving components.