Answer:
They allow a reduction in chromosomes while preserving most of the cytoplasm for one egg.
Step-by-step explanation:
In ovary oogenesis occurs for the formation of ovum or egg.
During oogenesis primary oocyte on meiosis - I forms one secondary oocyte and one polar body.
In the next step secondary oocyte on meiosis-II forms one ovum and one polar body.
Polar bodies are small cells which have less cytoplasm.
Polar bodies are meant for preserving cytoplasm to ovum so that ovum is rich in cytoplasm and it has only half of the chromosomes.