Why is the human female called a default sex?

The human male and female bird are heterogametic,while the human female and male bird are homogametic .Why they are called so?

Why male is called heterogametic sex?

Why are human females rarely haemophilic?

Why is the X-chromosome called sex chromosome?

Why males are called heterogematic sex?

Fill in the blanks : The male and female sex organs in bryophytes are called as ………… and …………. Respectively.

The menstrual phase in human female is also called _____ phase .

What are female sex cells called?

Why woman is called homogametic sex?