How can an individual carry a defective gene but not exhibit the defective phenotype?
a) An individual may not have that defective gene in every cell, and so appear normal
b) Individuals carry two copies of gene instructions, and one dominant allele could mask the presence of a recessive defective allele
c) Individuals are always homozygous
d) Both a) and c) are true
e) None of the above is true
Ans: b) Individuals carry two copies of gene instructions, and one dominant allele could mask the presence of a recessive defective allele
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