Question

read the passage.
the evolving human skeleton
our early ancestors were hunter - gatherers who obtained food by hunting and by searching for edible wild plants. they needed strong bones, including large, strong jaws that enabled them to eat tough, uncooked foods. when our ancestors developed agriculture, however, their diet changed. they began growing plants, such as grains and beans, and raising animals for food; they also started cooking their foods, making them softer and easier to chew. consequently, the human skeleton underwent radical changes. over time, the human jaw became smaller and changed shape. other bones also evolved, becoming lighter, especially in the joints, as a result of both dietary changes and a less active lifestyle.
what is the main, or central, idea of the passage?
as early humans developed agriculture, their bones changed significantly.
early humans ate uncooked meats and vegetables, so they needed strong jaws for chewing.

Explanation:

The passage describes how early human ancestors' shift from hunter-gathering to agriculture (with dietary changes like cooking softer foods) led to significant skeletal changes (e.g., smaller jaws, lighter bones). The first option captures this central link between agricultural development and skeletal changes, while the second is a supporting detail about early hunter-gatherers.

Answer:

As early humans developed agriculture, their bones changed significantly.