Both crystal violet and safranin are basic stains and may be used to do simple stains on gram-positive and gram-negative cells. This being the case, explain how they end up staining Gram-positive and gram-negative cells differently in the gram stain

Both the stain which is used in gram staining may be used to do simple stains on gram-positive and gram-negative cells but gram-positive bacteria end beings stained violet and gram-negative being stained pink because of the composition of their cell wall.

As the gram-positive bacteria have an outer thick layer of peptidoglycan it is not decolorized after destaining step and the mordant iodine also helps it to do that but as the gram-negative bacteria have outer LPS layer in cell wall so it get decolorized after destaining as alcohol in destaining step degrades some LPS layer.

So after counter staining the gram-negative bacteria appears pink and gram-negative bacteria retain crystal violet so they appear purple.

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 !