Final answer:
The two dune types common with two prevailing wind directions are Linear and Star dunes. Linear dunes form in areas with converging wind directions, while Star dunes arise from multi-directional wind regimes. The correct answer is option b. Linear and Star dunes
Step-by-step explanation:
Common Dune Types with Two Prevailing Wind Directions
The two dune types that are common with two prevailing wind directions are b. Linear and Star dunes. Dunes are formed when windblown sand accumulates in the terrestrial or desert landscape, and their shapes and types vary based on factors like wind direction, sand supply, and vegetation coverage.
Linear dunes, also known as longitudinal dunes, form parallel to the prevailing wind direction and can develop where there are two prevailing winds that converge at an acute angle. Star dunes are pyramidal sand mounds with slipfaces on three or more arms that indicate multi-directional wind regimes.
Unlike subaerial dunes which are formed by wind action and are commonly seen on beaches or in deserts, subaqueous dunes, or sandwaves, form under water bodies like rivers and oceans.