On mohs scale, ice has a hardness of 1.5. why can a glacier cause the grooves and parallel scratches (striations) found in bedrock of granite and gneiss? answer

The glacier carries along with ice, rocks that create the grooves and scratches. As a simple example, paper is relatively soft, yet sandpaper is quite capable of sanding substances with a mohs scale hardness of 9 or lower. Reason is quite simple. The sandpaper has embedded on its surface, silicon carbide which has a hardness of 9 to 9.5. And glaciers can carry boulders and rocks along their bottom surface which in turn can grind and scrape softer materials.

Your answer is d. silli hope this ! : ) i left an explanation down below if you need it: a sill forms when hot magma squeezes between layers of rock to form a hardened sheet of rock. a sill is basically a tabular sheet intrusion between old layers of sedimentary rock, volcanic beds, or in the direction of foliation inherent in metamorphic rock. the word sill means a concordant intrusive sheet.