Within the Tibetan highlander population, genetic variation has been found to determine relative oxygen-hemoglobin saturation levels. Individuals within this population may be homozygous for either the low oxygen saturation gene or the high oxygen saturation gene. Individuals may also be heterozygous, carrying one low and one high oxygen saturation gene. Based on this information, individuals within the population carrying __________________________ alleles are expected to demonstrate a physiological advantage for survival.homozygous low oxygen saturationheterozygous oxygen saturationhomozygous high oxygen saturation population