There are approx 100 billion
Answer:
The correct answer would be A. how living organisms interact and function.
The term biology comes from Greek words "bios" which means life and "logos" which means study.
Biology is defined as the natural sciences that study life and all the living organisms including their chemical processes, physical structures, development, physiological mechanisms, molecular interactions, and evolution.
Answer:
Tissue
Tissue is the group of similar cells that are common in origin to perform particular function. Tissue system is the group of similar tissues that are common in origin and perform particular function. Organs are made up of tissue system.
Explanation:

Air pollution has become an extremely serious problem. Air pollutants affect both plants and animals. Under polluted conditions, plants develop different physiological, morphological and anatomical changes. Pollutants cause damage to cuticular waxes by which then they enter the leaves through stomata. This further leads to injury to plants which can be either acute or chronic. Changes in stomata due to air pollutants which seem to be small can be of great consequence with respect to survival of the plant during stress. These effects can further lead to disturbing the water balance of leaf or whole plant. Respiration also gets affected because of the exposure of plants to air pollutants. The present paper deals with the effect of air pollutants on stomata as well as on respiration leading to affect gaseous exchange.

