Interspecific interaction could be

What is the nature of the interaction between methanogens and cattle?

$A$: An ecological niche is usually occupied by a single species.
$R$: More than one species can live in the same habitat.

Which of the following definitions is most appropriate for competition?

In an aquarium,two herbivorous species of fish are living together and feeding on phytoplanktons. As per the Gause's Principle,one of the species is to be eliminated in due course of time,but both are surviving well in the aquarium. Give possible reasons.

The interaction between two living organisms of different species which is beneficial to both but is not obligatory because they can live without each other is known as