What is the ovum doing during the primary oocyte stage?

Explanation:

The process of formation of Oocytes is called Oogenesis.It id the equivalent of spermatogenis in males.it begins in the ovaries where the oocytes divides to form oogoinia by mitosis.

The oogonia under grows growth,and These cells undergo further divisions by meiosis,but the meiotic division is restricted to Prophase 1 of meiosis.These diploid cells are called primary Oocytes,and all further division from this stage remains  till puberty in girls.

Generally in Prophase 1 of meiosis of any dividing cells the following activities  occurs:

1 The nuclear envelope breakdown

2. Bivalent forms and Crossing over  of chromatids occurs

3,the nucleoli disappears.

Since the ovum stops at Prophase 1  to form primary oocyte during Oogenesis,therefore these are what occurs in ovum at the primary oocyte stage.