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

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.

the cost of mining is extremely low compared to the money earned from mining, creating income to improve the environment.