Answer:
meiotic prophasel
Explanation:
Crossing-over is a unique phenomenon that only occurs during meiotic division or gamete formation. It is the process whereby non-sister chromatids of homologous chromosomes exchange a portion of the their chromosome.
Crossing-over occurs specifically in the Prophase 1 stage of meiosis, where homologous chromosomes lie side by side to form a TETRAD structure and exchange their chromosomal segment. Crossing-over aims at promoting genetic diversity among sexually-reproducing organisms.
Therefore, an ovarian slide observed to show crossing-over occurs at the Prophase I stage of meiosis 1.
