How is the effective dosage of x-linked gene products balanced in placental mammals between females that carry two x chromosomes and males that carry only a single x chromosome?

According to the Lyon's hypothesis, the dosage compensation in the placental mammals takes place by inactivation of one of the X chromosome in the female somatic cells. The dosage compensation is a process, by which the expression of the chromosomes is balanced between the sexes.

The inactivated X chromosome causes the formation of the barr bodies in females.

a scenario where a cell may be needed to perform a form of endocytosis is when transporting large molecules. a scenario where a cell may be needed to perform a form of exocytosis is when releasing the large molecule from the cell.