Which of these situations does not have quantities that combine to make 0? O A. A car is filled with 10 gallons of gas. 10 gallons are then used in a drive across the state. O B. A dolphin swims 20 feet straight down from the surface. It then rises 20 feet to return to the surface. O C. Mary receives $26 for babysitting. She then spends $26 on a new jacket. O D. 4 cups of water are added to the mixture. Then 4 cups of flour are added.

The greatest gift the sumerians gave the world was the invention of writing. the sumerians were 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.