Final answer:
Early Israelites were primarily distinguished from others in the Fertile Crescent by their monotheistic belief system, whereas other cultures practiced polytheism.
Step-by-step explanation:
The early Israelites differed from other cultures in the Fertile Crescent primarily through their religion. They had a monotheistic belief system, which was very distinct in a world where many cultures, including those in the Arabian Peninsula, practiced polytheism and worshipped a variety of gods and goddesses. The development of Hebrew monotheism began with figures such as Abraham and was further shaped during the time of Moses, who emphasized worship of a single god, Yahweh. The eventual establishment of this monotheistic worship was solidified into the Jewish religion, significantly differing from the polytheistic and animistic traditions prevalent in the Fertile Crescent and surrounding areas at the time.