I have a question:
 In Taxonomy, why species having inferior ovary are considered advanced than species containing superior ovary.
A flower has four series on thalamus from base to top: calyx, corolla, androecium (stamens) and Gynoecium (Carpels with ovary at base). Naturally ovary is superior to all other whorls. flower hypogynous; during the course of evolution ovary becomes  inferior due to two reasons:
 1. calyx fuses with ovary (consequently corolla also) so that ovary (with ovules inside) appears lower than other whorls (consequently inferior): flower epigynous.
 2. There is axial invagination of thalamus so that ovary (and carpels) lie at bottom of the depression (ovary semi-inferior); flower pergynous
 I hope that helps
Thank you so much sir… Indeed a helpful answer.