Individuals occupying a particular habitat and adapted to it phenotypically but not genotypically are known as
Ecophenes
Ecotypes
Ecospecies
Coenospecies
The term 'ecad' was proposed by Turesson (1922) for the individuals in a particular population occupying a particular habitat and adapted to it phenotypically, but never genotypically. It is also often known as 'ecophene'. Variations produced by an 'ecad' are environmentally induced, temporary and reversible. Hence, the correct answer is option 1.