Peolple living at high altitudes generally have more hemoglobin in their blood than people living at sea level. why do you think this is so

Waianapanapa beach in hawaii is a black-sand beach that was formed by waves crashing against volcanic rock. the sand can be very hot on sunny days. which statement best explains why? o a. the black sand has no heat capacity. b. the black sand absorbs no radiation. o c. the black sand is immune to insolation. d. the black sand has a low albedo.