Concept:When many organisms depend on the same limited supply of resources, they are forced to struggle against one another to obtain enough for survival.
Explanation:Resources such as food, water, space, and light are often limited in nature.
When a large number of organisms require the same limited resources, they cannot all get enough.
This creates a direct or indirect struggle among the organisms for those resources.
This interaction is known as competition.
Competition may occur within the same species, called intraspecific competition.
It may also occur between different species, called interspecific competition.
The competing organisms try to outgrow, outbreed, or gain better access to the available resources.
As a result, some individuals may fail to get enough resources, which can affect their growth, survival, or reproduction.
Competition is therefore a major ecological factor that influences population size and distribution.
Mutualism and commensalism are both beneficial or neutral relationships, not struggles for resources.
Extinction is an extreme possible outcome, but it is not the immediate result of resource sharing.
Therefore, the correct ecological term for this situation is competition.
Answer:D. competition