Riprap added to the base of a steep slope .A. absorbs wave energy and can slow the undercutting of coastal cliffs. B. can make the slope less stable. C. should be removed before it causes a rockfall. D. is a useful way to prevent avalanches.

Rip-rap called as rock shield is the man-made rock that is used as a shields to protect the shoreline, streambeds and bridges and the other structure against the water, waves, and ice erosion and the most common type includes granites and concrete.

Hence the option A is correct in that it absorbs the wave energy and can also slow the undercutting of the coastal cliffs.

Learn more about the Riprap to the base of the steep slope.

radiative zone

explanation    

radiative zone is the layer of the sun which energy is transferred away from the core by radiation. although, the core is the only part of the sun that produces an appreciable amount of heat through fusion. in fact, 99% of the energy produced by the sun takes place within 24% of the sun's radius.