I think can be water, light, temperature, nutrients
Hope help!
Answer:
Many small organisms can be preserved within these layers of sediment through time. The changing abundances of these fossils through time can tell us whether a change in the environment or climate was gradual or abrupt. Studying fossil pollen and other fossils helps scientists to learn more about climate change.
A sonar is an underwater sound detecting system.
No organism is always the first step, except in a wide sense, plants. In the water, plankton is found in first but whereas on land, plants or seeds are eaten first.
Hope it helped!! :)
