The nuclear family is especially well adapted to a mode of subsistence that requires:​

A) ​healthy children
B) ​accumulated wealth
C) ​a large labor force
D) ​a high degree of geographical mobility

Subsistence

The means by which individuals or societies obtain their basic necessities for survival, such as food, shelter, and clothing.

Geographical Mobility

The movement of people or populations from one location to another, often for reasons of employment, housing, or other socio-economic factors.