Final answer:
Foraging societies, also known as hunter-gatherer societies, relied on hunting and gathering for survival. They were not self-contained and engaged in trade or barter.
Step-by-step explanation:
Hunter-gatherer societies, also known as forager societies, relied on hunting wild animals and gathering uncultivated plants for food. They were nomadic, moving to new areas to find sustenance when resources became scarce. While they did not typically possess the skills to build other types of shelter like caves, they did engage in other modes of subsistence such as limited trade or barter. Therefore, statement a is correct, statement b is incorrect, statement c is incorrect, and statement d is incorrect.