Step 1: Understanding the Concept
A niche is the functional role of a species: what it eats, where and when it is active and how it interacts with its surroundings.
Step 2: Check the statements
A niche is an activity or role performed by an organism, true. It supports a single species at a time, true. Through the trophic position, it relates to energy flow between organisms, true.
Step 3: Find the false one
A niche is species specific, because by the competitive exclusion principle no two species keep the same niche for long. So saying it is not species specific is incorrect.
Final Answer:
The incorrect statement is that a niche is not species specific.
\[ \boxed{\text{(A) }\text{It is not species specific}} \]