Concept:The atmosphere is the gaseous layer surrounding the earth, supplying essential gases for life processes.
Explanation:Option A refers to the hydrosphere, which deals with water bodies.
Option C refers to the biosphere, since timber is obtained from living plants.
Option D refers to the lithosphere, because roads and railways are constructed on the earth's crust.
The atmosphere provides oxygen needed for respiration by animals and plants.
It also contains carbon dioxide for photosynthesis and nitrogen for plant protein formation.
Thus, the major importance of the atmosphere to living organisms is the supply of respiratory gases.
Answer:B. It provides oxygen for animals and plants for respiration