Question

carriers of recessive disorders are __________. a homozygous dominant b heterozygous c homozygous recessive d either heterozygous or homozygous recessive

Explanation:

• Homozygous dominant: Individuals with this genotype have two dominant alleles. They do not carry the recessive allele for the disorder, so they cannot be carriers.
• Heterozygous: Carriers of recessive disorders have one dominant allele (which masks the recessive allele's effect, so they do not show the disorder phenotype) and one recessive allele (which can be passed on to offspring).
• Homozygous recessive: These individuals show the recessive disorder phenotype (as there is no dominant allele to mask the recessive one), so they are not carriers but affected by the disorder.
• Either heterozygous or homozygous recessive: Homozygous recessive individuals are affected, not carriers. Only heterozygous individuals are carriers.

Answer:

B. heterozygous