What factor most likely determined how often a nomadic group moved? the lack of geographical protectionthe lack of close proximity to a river or lakethe group's boredom with the surroundingsdwindling food supplies

dwindling food supplies

Explanation:

Nomadism is a form of life that was present in human groups, especially before the Agricultural Revolution. It is a human practice of groups that, instead of living fixed in one place, scatter around the territory looking for food. Their walk revolves around the natural resources available: when they were depleted, they moved to other places. Between 1 million years and 10,000 years, humanity lived in a nomadic way. According to this reasoning, we can say that the correct answer to your question is "dwindling food supplies".

no statements but ok.

the statement that best describes the idea of manifest destiny that was used in the 19th century would be that "it was fate that the united states would continue to  expand westward," since people thought the us was "destined" to do so. 

worldwide, 780 million people do not have access to an improved water source. an estimated 2.5 billion people lack access to improved sanitation (more than 35% of the world's population)