In all organisms, genes are found on chromosomes, and genes regulate genetic characteristics.

In most organisms, all these chromosomes are found in pairs, meaning there are two copies of each chromosome.

For example, there are a total of 23 pairs of chromosomes in humans or 46 chromosomes are found in number.

The first 22 (44 in number) pair  of chromosomes are called autosomes or somatic chromosomes.

Autosomes are chromosomes that, apart from sex determination, regulate other characteristics of the body.

The same pair (23rd XY or XX) are chromosomes, which are called sex chromosomes or allosomes.

Sex chromosomes are chromosomes that play a major role in sex determination.

The sex chromosomes in the mail are denoted by X and Y, that is total number of chromosomes in the mail will be 44+XY.

In females, the sex chromosomes are denoted by two XX chromosomes, which means that the total number of chromosomes in males will be "44+XX"