Answer:
D. because water and mud behaved in a similar way in the past as they do today
Explanation:
One of the fundamental theories in the field of earth science is the theory of uniformitarianism.
Uniformitarianism was proposed by James Hutton in the 18th century in Scotland. The theory states that "geologic processes occurring today have occurred in times past and that the present is the key to past".
The simple meaning of the theory is that, the processes on earth today such as weathering, erosion, e.t.c have also occurred in times past. Those processes still occur today and an understanding of such events today will help us have a better insight into the past.
Therefore, ripple marks just as they form today from action of mud and water would be formed in a similar way in the past.
The change that would need to be made to the slit spacing in order to see a diffraction pattern is bending, because in understanding why light behaves like a wave, it is the interference and diffraction were the phenomena distinguish waves from particles but waves are the only one can interfere and diffract while particles do not. The light bends around obstacles or cylinder like waves do, then it is bending which cause and resulted in the single slit diffraction pattern.
When that happens, you get a plasma — the fourth state of matter.