Alleles and Genotype Formation in Mendelian Genetics

Steps:

• Identify alleles as variant forms of a gene: A (dominant) and a (recessive).
• Determine possible genotypes for a diploid organism: homozygous dominant (AA), heterozygous (Aa), homozygous recessive (aa).
• Evaluate diagrams for accurate labeling of alleles A and a plus these three genotypes.
• Select the diagram matching this standard representation.

Why C is correct:

• It labels alleles A and a and shows all three genotypes (AA, Aa, aa) as defined by Mendel's law of segregation.

Why the others are wrong:

• A: Omits heterozygous genotype Aa.
• B: Mislabels alleles or shows incorrect combinations like AA and aa only.
• D: Includes invalid genotypes or confuses alleles with phenotypes.

Not enough information on exact diagram details, but C aligns with core concepts.

Final answer: C