Final answer:
Below-replacement-level fertility is typically found in industrialized or post-industrial societies with consumer economies that focus on high mass consumption, where urbanization and higher living standards lead to smaller family sizes.
Step-by-step explanation:
The mode of livelihood often associated with below-replacement-level fertility is the consumer economy observed in industrialized or post-industrial societies. In this stage 5 economic development, the focus is on high mass consumption, leading to higher living standards and smaller family sizes, commonly resulting in fertility rates below the replacement level of 2.1 children per woman.
A clear shift from an agrarian, rural society to an urban, consumer-based economy correlates with the decreasing total fertility rate. With increased urbanization and industrial activity, family sizes generally become smaller due to the variety of opportunities and changes in societal values and lifestyle expectations.
This trend is substantiated by data from the World Development Indicators database, highlighting the difference in fertility rates between low-income nations (higher fertility rates) and high-income nations (lower fertility rates).