7.angular grains in a clastic sedimentary rock indicate

a. the absence of cleavage in the mineral clasts.

b. rapid, typically short-distance transport.

c. numerous collisions between particles during extensive transportation.

d. lack of chemical weathering.

c. numerous collisions between particles during extensive transportation.

Explanation:

A clast is a smaller grain of the rock broken off by the other rocks occurring by the physical weathering or whether in suspension as a bedload and occurs in sediment deposits. The angular grains that formed due to the erosion of clastic rocks that form part of the sedimentary rocks are an effect of the mineralogical components of the rocks that make up the blogs of the silicate particles that are derived from the weathering of the older rocks namely as in the form of Conglomerates and breccias, Sandstones, and the Mudrocks. Thus there are changes in the composition, and texture of the rocks surfaces and an example of a clastic environment could be a river system where the full range of grains are being transported by the moving water consist of eroded particles from solid rock upstream.

81 is a composite number

Answer sinking and cooled;