问个og的阅读

shuibanqing

A green iceberg that stranded just west of the Amery Ice Shelf showed two distinct layers: bubbly blue-white ice and bubble-free green ice separated by a one-meter-long ice layer containing sediments. The green ice portion was textured by seawater erosion. Where cracks were present, the color was light green because of light scattering; where no cracks were present, the color was dark green. No air bubbles were present in the green ice, suggesting that the ice was not formed from the compression of snow but instead from the freezing of seawater. Large concentrations of singlecelled organisms with green pigments (coloring substances) occur along the edges of the ice shelves in this region, and the seawater is rich in their decomposing organic material. The green iceberg did not contain large amounts of particles from these organisms, but the ice had accumulated dissolved organic matter from the seawater. It appears that unlike salt, dissolved organic substances are not excluded from the ice in the freezing process. Analysis shows that the dissolved organic material absorbs enough blue wavelengths from solar light to make the ice appear green.



7. Why does the author mention that “The green ice portion was textured by
seawater erosion”?
_ To explain why cracks in the iceberg appeared light green instead of dark green
_ To suggest that green ice is more easily eroded by seawater than white ice is
_ To support the idea that the green ice had been the bottom layer before capsizing
_ To explain how the air bubbles had been removed from the green ice
为啥选C呢，好像找不到线索从原文