scientists divide geological time into eras and periods. the is most inclusive, and the boundaries are based on .

How long does it take neptune to orbit the sun?

Which year held a congressional election and a presidential election

Ahis which describe the horizons in a soil profile? check all that apply. horizon a is mineral deficient. bedrock lies below the soil layers. te horizon o forms from organic material, horizon b undergoes the least amount of change. horizon c is least affected by the soil formation process.