The sex chromosomes of a human female are:

**The reasoning** Humans have 23 pairs of chromosomes (46 total). Twenty-two pairs are autosomes (same in males and females), but the 23rd pair determines biological sex — these are the **sex chromosomes**. Females have **two X chromosomes (XX)** — one from each parent. This XX combination triggers female reproductive development. Males, on the other hand, have **one X and one Y chromosome (XY)** — the Y chromosome carries genes that initiate male development. So: **Female = XX**, Male = XY. Simple pattern to remember! **Why the wrong options tempt you** - **XY** might confuse you if you mix up male and female patterns - **YY** doesn't naturally occur in humans — every person needs at least one X chromosome to survive - **XO** (Turner syndrome) is a rare genetic condition where a female has only one X chromosome instead of two, but it's abnormal, not the standard female pattern **Quick takeaway** Think "**XX = double X = female**" — the double letter matches how we often emphasize femininity, while XY is the mixed pair for males.