What happened after the serpents appeared and bit the israelites

The Israelites were infected, so Moses crafted a bronze snake that when the Israelites looked upon it, they were healed. 

During the paleolithic, hominins grouped together in small societies such as bands, and subsisted by gathering  plants  and fishing, hunting or scavenging wild  animals. the paleolithic is characterized by the use of knapped stone tools, although at the time humans also used  wood  and bone tools.

Clean air provides nitrogen