because they have have negligible mass
It’s living vs non living
Fundamental niche is the job/role that one species can have in the environment .
The realized niche is the role of a species influenced by several factors in the environment.
Example:
The fundamental niche of Yellow Warblers is found in a spruce tree.
The realized niche of the Yellow warblers is when they are "forced" to share the spruce tree and remain in one particular area of the tree while other warbler species play defense different niches in other parts of the tree.
:v it is like :
•Fundamental niche: [yellow warbler] "I got my home, all for me..."
~new species arrive to the spruce tree~
•Realized niche: [yellow warbler] oh, shoot! I gotta stay in the upper part/move to the upper part as the others warbler "struggle" to get territory :v or they just choose their own . :v
Answer:
The atmosphere is the largest reservoir of the nitrogen as it is composed of 78% of Nitrogen. Although 78%, this is not used by the organisms directly as the nitrogen molecule exists in nature in the form of divalent joined via triple bonds.
These triple bonds require a great amount of energy to be broken and used. Only a few prokaryotic organisms called nitrogen-fixing bacteria have the capability to break these triple bonds as they contain enzymes-nitrogenase complex which converts the atmospheric nitrogen to usable forms like ammonia, nitrates and nitrites. About 92% of the atmospheric nitrogen is fixed through this way rest through thunderstorms and Haber's process.
Thus, nitrogen-fixing bacteria is the answer.
It's some change in the conditions around the organism, which the organism can detect and respond to. A change in temperature, more light, or something physically poking the organism are examples.