Can a lunar eclipse cause erosion

Which of the following natural processes is most likely to support the formation of an underwater sinkhole? a pollution buildup from deposited minerals b limestone cave collapsing due to changes in sea level c erosion of large amounts of sand moved by ocean waves d oxidation of rock formed by chemical weathering

Which terms are used to identify pure substances

What is the wavelength of a wave with a velocity of 50 m/s and a frequency of 5hz a 250 m b 0.1 m c 10m d 0.01 m