Cells that lack checkpoints and fail to respond to cell cycle controls are: o A. Embryonic cells in the process of development; they have not yet established their checkpoints
O
B. Amniotic cells like epithelial cells
O
C. Defective, and may be cancerous
O
D. Those that divide at a steady rate regardless of environmental conditions

stratosphere: as the altitude increases, the air temperature increases. the stratosphere has a layer of ozone, called the ozone layer. this layer absorbs most of the ultraviolet radiation from sunlight. this results in the stratosphere being warmer.

oceans

indian ocean

pacific ocean

atlantic ocean

arctic ocean

southern ocean

geologic time scale (for gradpoint) =)