Do you think those barriers have been affective against erosion?​

One of the main reasons societies settled along rivers in the neolithic era was because a) the village elders demanded it. b) the land there was more valuable. c) it was more safe and secure there. d) it provided irrigation for farming.

Ozone in the upper atmosphere has been depleted by a. sulfur dioxide. b. chlorofluorocarbons. c. carbon dioxide. d. oxygen.

The earth rotates on its axis and revolves around the sun every