They feel that we should be fully aware of our own environment.

Answer: Option D

Heredity : the passing on of physical or mental characteristics genetically from one generation to another.
Family : a group consisting of two parents and their children living together as a unit.
Nationality : the status of belonging to a particular nation.
Surroundings : the things and conditions around a person or thing.
Environment : the surroundings or conditions in which a person, animal, or plant lives or operates.

Synonym of Environment is Surroundings