A) what two processes account for adding free oxygen to the precambrian atmosphere? b) what do we mean by free oxygen, and c) which of these two processes were most important?

read the sentence below and answer the question that follows. one of the norms in the village was to meet at the town square on fridays for a community dinner and dance. the underlined word in the sentence above is best defined as a a. cultural element shared by all people around the world b. specific area in a town used for traditional community events c. religious custom accepted and practiced by all members of a village d. behavioral pattern that is regularly accepted by a group of people

answer; (d) melting of sea ice;