Question

A biosphere is composed of
A. Living organisms
B. Living organisms + lithosphere
C. Living organisms + lithosphere + atmosphere
D. Living organisms + lithosphere + atmosphere + hydrosphere

Answer 1

Hint: The biosphere is a global ecosystem having both biotic and abiotic components. The biotic components derive their energy and nutrients from non-living factors like the atmosphere, water, and land.

Complete answer: The biosphere refers to the sum of all the ecosystems present on earth. It consists of biotic components which are the living organisms or biota. Living organisms range from microbes to complex large animals like elephants. The second component of the biosphere is abiotic factors or non-living factors mean the environment. The non-living factors include the hydrosphere which is total water bodies, lithosphere that consists of land, mountains, or rocks and, the atmosphere that includes gases.
Option A is living organisms. The biotic components are part of the biosphere but cannot exist without interaction with the abiotic components of the biosphere.
Option B is living organisms and lithosphere. Biotic components utilize the lithosphere as their habitat. But marine biota cannot survive without a hydrosphere. All the biotic components require oxygen that is derived from the atmosphere. Thus only biotic factors and lithosphere cannot make a biosphere.
Option C is living organisms, lithosphere, and atmosphere. All these components are part of a biosphere. But without a hydrosphere, the organism will die soon and thus cannot survive without water.
Option D is living organisms, lithosphere, atmosphere, and hydrosphere. This is the right option as it contains all the necessary components required for the survival of biotic components and the balance of the ecosystem.
Thus, the right answer is option D

Note: The two main components of the biosphere are living and non-living units. The living organisms derive their nutrition from non-living components and sustain their lives. The non-living units take care of the balance of the ecosystem. They regulate population levels to create a sustainable biosphere.