Step 1: Understanding the term "niche".
In ecology, a niche is defined as the role or position of a species in its environment, including how it interacts with biotic factors (living organisms such as predators, prey, competitors) and abiotic factors (non-living conditions such as temperature, light, rainfall, soil nutrients).
Step 2: Differentiation from other ecological terms.
- A habitat is simply the "address" of a species (where it lives).
- A niche is its "profession" (how it lives and interacts).
- An ecotone is the zone of junction between two ecosystems.
- Only abiotic factors = part of niche but not the complete definition.
Step 3: Evaluate options.
- (B) Incorrect → Niche is not only abiotic, it includes biotic.
- (C) Incorrect → This describes an ecotone gradient, not niche.
- (D) Incorrect → A transition zone is ecotone, not niche.
- (A) Correct → Matches full ecological definition.
\[
\boxed{\text{Interaction with biotic and abiotic factors of the environment}}
\]
% Quicktip
P and Q play chess frequently against each other. Of these matches, P has won 80% of the matches, drawn 15% of the matches, and lost 5% of the matches.
If they play 3 more matches, what is the probability of P winning exactly 2 of these 3 matches?
In a regular semi-circular arch of 2 m clear span, the thickness of the arch is 30 cm and the breadth of the wall is 40 cm. The total quantity of brickwork in the arch is _______ m\(^3\). (rounded off to two decimal places)

Identify the option that has the most appropriate sequence such that a coherent paragraph is formed:
Statement:
P. At once, without thinking much, people rushed towards the city in hordes with the sole aim of grabbing as much gold as they could.
Q. However, little did they realize about the impending hardships they would have to face on their way to the city: miles of mud, unfriendly forests, hungry beasts, and inimical local lords—all of which would reduce their chances of getting gold to almost zero.
R. All of them thought that easily they could lay their hands on gold and become wealthy overnight.
S. About a hundred years ago, the news that gold had been discovered in Kolar spread like wildfire and the whole State was in raptures.