What is the geological time scale based on?

The geological time scale refers to the arrangement of major and distinguishable events that have taken place in the geological past and also provides a glimpse of how the earth and the organisms have undergone significant evolution over a due course of time. It is based on the presence of fossils on the rocks of various sequences, and also the classification of rock types and the correlation of rocks of different locations.  It shows right from the time of formation of the earth, which is approximately 4.6 billion years ago.

This time scale is one of the main components of geology and is widely used by the paleontologists, geologists and other earth-related scientists, in order to construct the relation of various events that have occurred in the past.  

d concave shape of wave rock

explanation:

the concave shape of wave rock is a very good evidence that supports the evolution of earth due to chemical weathering. if we talk about structure of   wave rock, studies have estimated that it is around 2.7 billion years old. it also serves as the foundation of evidence that it was the place where australian continent began to form.

how the structure of wave rock was created?

studies suggest that structure of wave rock was created when the surrounded area was started to weather due to which deposition of material started on the part of land which now contains wave rock.

the structure of wave rock is considered to be one of the best-known landforms in australia. at the height of around 15 cm, there can be found flared slopes which formulate the margins of hyden rock. it is now assumed by geologists that wave rock was created by subsurface water-induced weathering and not by glaciers, waves or wind.

due to deposition of material over the period of long time, the wave rock became tougher and tougher due to weathering from surrounding terrain. this makes it a physical evidence that supports   the evolution of earth due to chemical weathering.

hope it !

b. the carbon cycle ensures living things have a source of hydrogen