Step 1: Chromosome with the highest number of genes. - Chromosome 1 has the highest number of genes, with approximately 2,000–3,000 genes.
Step 2: Chromosome with the least number of genes. - Chromosome Y has the least number of genes, with around 50–60 functional genes.

Study the diagram above and answer the following questions:
(a) How many alleles are involved in blood grouping?
(b) A person having 'AB' blood group has both dominant alleles. What is this inheritance type called?
(c) A man with 'A' blood group marries a woman with 'B' blood group. Can they have a child with 'O' blood group? Explain with the help of a cross.