How do these substances produce light of different colors?

Every substance produces light of different colors on the basis of level of energy that is possessed by the electrons of a substance.

Explanation:

Every substance has its level of energy. Depending upon that energy level the light of different colors id produced. There are electrons present in every substance that is made up of atoms and those atoms consist of electrons.

Whenever an atom is heated, the electrons present get excited and their energy level also increases but when their energy level comes down they emit energy in the form of light. The color of that light depends upon the level of energy of an electron. Each substance emits its color.

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 !