(N/A) typical angiosperm flower consists of four whorls arranged sequentially from the outermost to the innermost as follows:
$(a)$ Calyx: It is the outermost whorl of the flower. Its individual units are called sepals. They are generally green in color and protect the flower in the bud stage.
$(b)$ Corolla: It is the second whorl,composed of petals. They are often brightly colored to attract insects for pollination.
$(c)$ Androecium: It is the third whorl,composed of stamens. It is the male reproductive organ. Each stamen consists of a filament (stalk) and an anther,which contains pollen sacs and pollen grains.
$(d)$ Gynoecium: It is the innermost whorl,composed of one or more carpels (pistils). It is the female reproductive organ,consisting of the ovary,style,and stigma.