Question

understanding scientific texts — instruction — level c
rising water is eroding, or wearing away, the banks of the ningliq river.
the rising river isn’t the only danger to the people of niugtaq. the village sits on top of a layer of frozen soil called permafrost. permafrost is found underground in the far northern part of the world. permafrost usually stays frozen all year long. but because temperatures are rising, the permafrost in alaska has started to melt. when permafrost melts, the ground above it starts to sink. when the ground sinks, so do the structures on top of it. as a result, many of the buildings in niugtaq are no longer safe.
fill in the blanks to explain the effects of the melting permafrost in niugtaq.
as permafrost melts, it causes the ground to freeze, rise, sink. as a result, text cut off on top of the ground be...

Explanation:

From the text, it is stated that "When permafrost melts, the ground above it starts to sink". So the correct word to fill in the blank is "sink" as it matches the described effect of permafrost melting on the ground.

Answer:

sink