Which of the following data supports the nebular hypothesis? Select all that apply. A. The planets in our solar system revolve in different directions.
B. The planets in our solar system all revolve in the same direction.
C. The planets in our solar system are spread out in a specific pattern.
D. The planets in our solar system orbit the Sun in the same flat, disc-shaped region.

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.