________ is not part of the whorls of a flower.

Explanation

This Biology question is asking which of the options given is not part of the whorls of a flower. Whorls are the circular or spiral arrangements of flower parts. The options provided are calyx, corolla, androecium, antheridium, and gynoecium. Calyx and corolla are parts of the outer whorl of a flower and are collectively called the perianth. The calyx is the outermost whorl of the flower and is made up of sepals while the corolla is the second whorl and is composed of petals. Both the calyx and corolla are involved in protecting the reproductive parts of the flower. Androecium and gynoecium are parts of the inner whorls of a flower. The androecium is the male reproductive part of the flower and is composed of stamens which have an anther that produces pollen. The gynoecium is the female reproductive part of the flower and is made up of the pistil which has the ovary, style, and stigma. Antheridium, on the other hand, is not part of the whorls of a flower. Antheridium is a structure found in some lower plants like algae, mosses, and ferns. It is the male sex organ that produces and releases sperm. Therefore, option D is correct. In summary, the whorls of a flower are made up of calyx, corolla, androecium, and gynoecium. Antheridium is not part of the whorls of a flower, as it is a reproductive structure found in some lower plants.