Eras, like the paleozoic, mesozoic, and cenozoic periods are separated into periods by which marker? question 4 options: changes in rock layers species extinction 100 million year chunks the types of living organisms that were present

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.