How an organism is suited to live in a particular place is called

Adaptation is how an organism becomes suited, through inherited features, to live and thrive in a particular place.

Competition is the struggle between organisms for shared resources, not fitness to a habitat.

Addition is not a biological term for suitability to an environment.

Participation is not a term describing an organism's fitness to its surroundings.

Adaptations may be structural, physiological or behavioural and arise through natural selection.

A camel's water conservation and a cactus's spines are classic examples of adaptation.