In genetic crosses, the symbols AA and Aa refer respectively to:
A)heterozygous and homozygous phenotypes.
B)heterozygous and homozygous genotypes.
C)homozygous and heterozygous phenotypes.
D)homozygous and heterozygous genotypes.
E)homozygous and heterozygous morphotypes.

Question

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In genetic crosses, the symbols AA and Aa refer respectively to homozygous and heterozygous genotypes. "Homozygous" means that two alleles of a gene are the same (in this case, both are "A"), while "heterozygous" means that two alleles of a gene are different (in this case, one is "A" and one is something else, probably "a"). The terms "phenotype" and "morphotype" refer to physical traits or characteristics, not to the genetic makeup of an organism.

In Genetic Crosses, the Symbols AA and Aa Refer Respectively