In some flowers the ovary is hidden deep within the base of the flower while the pollen is held up in the air, often near a source of nectar. how is this general design hepful to the plant

The pollen, petals, and nectar both serve to attract insects. The ovary, which is delicate and not meant for attracting organisms, could get damaged. The ovary is placed inside so it has some soft of protection, as it carries out an important in plant reproduction.