Biotic factors include plants, animals, microbes, etc. The important abiotic factors include the amount of sunlight in the ecosystem, the amount of oxygen and nutrients that is dissolved in the water, temperature, etc. Sunlight is one of the most important abiotic factors for marine ecosystems.
Would react with metals to form a slat and water
The fossil record is used to divide Earth's history into geologic time periods. The figure below shows the four major subdivisions of geologic time—eons, eras, periods, and epochs. Eons are the longest subdivision and are based on the abundance of certain fossils. Eons are divided into smaller time periods called eras
