The recessive character typically is expressed only when present in a double recessive condition. But, a single recessive gene can express itself in humans when genes are found on

The correct option is X chromosome of male.

In genetics, chromosomes are classified into autosomes (non-sex chromosomes) and sex chromosomes (allosomes). Humans have 22 pairs of autosomes and 1 pair of sex chromosomes. Females possess two X chromosomes (XX), while males possess one X chromosome and one Y chromosome (XY).

For genes located on autosomes in both sexes, or on the X chromosomes in females, individuals have two alleles (copies) for each gene. A recessive trait will only express itself if both alleles are recessive (homozygous state), such as aa or X^aX^a. If a dominant allele is present (heterozygous state, such as Aa or X^AX^a), the recessive trait is masked.

In contrast, males have only one X chromosome. Because the Y chromosome is much smaller and does not carry homologous alleles for most genes on the X chromosome, males are hemizygous for X-linked genes. This means that a single recessive allele located on the X chromosome of a male (X^aY) has no counterpart to mask it, allowing the recessive character to be fully expressed.