Answer:
hailstones --> Hail is a type of precipitation, or water in the atmosphere. Hail is formed when drops of water freeze together in the cold upper regions of thunderstorm clouds. These chunks of ice are called hailstones. Most hailstones measure between 5 millimeters and 15 centimeters in diameter, and can be round or jagged.
i am sorry i can not answer the oxygen question because it is not all there.
The two main groups of sedimentary rocks are clastic and chemical.
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