Which statement is best supported by text evidence from the excerpt?

By comparing part 1 and 2 of polar opposites what does it mean by polar opposites

The greatest gift the sumerians gave the world was the invention of writing. the sumerians were a wealthy people. they needed some way to keep track of what they owned. they began drawing pictures. they used a reed as a pen. they drew on soft pieces of clay. the soft clay was then dried in the sun. the tablet became a permanent record. later, the sumerian drawings changed into wedge-shaped symbols. this kind of writing is called cuneiform. by putting symbols together, the sumerians could write entire sentences.

Which of the following factors most consistently contributes to the speaker’s believability? a the age and experience of the speaker b the physical environment in which the speech is delivered c the sincerity, knowledge, and trustworthiness of the speaker d the position of the thesis statement in the speech