Question

Three features which distinguish angiosperms are:

• A. Naked seeds, flowers, double fertilization
• B. Double fertilization, covered seeds, flowers
• C. Dominant gametophyte, covered seeds, flowers
• D. Dominant sporophytes, naked seeds, double fertilization

Answer 1

The correct option is B

Double fertilization, covered seeds, flowers

Double fertilisation, seeds covered by fruit wall and flowers are characteristics of angiosperms. Unlike the gymnosperms where the ovules are naked, in the angiosperms or flowering plants, the pollen grains and ovules are developed in specialised structures called flowers. In angiosperms, the seeds are enclosed by fruits. The male sex organs in a flower is the stamen. Each stamen consists of a slender filament with an anther at the tip. The anthers, following meiosis, produce pollen grains. The female sex organs in a flower is the pistil or the carpel. Pistil consists of an ovary enclosing one to many ovules. Within ovules are present highly reduced female gametophytes termed embryo sacs. The pollen tubes enter the embryo-sac where two male gametes are discharged. One of the male gametes fuses with the egg cell to form a zygote (syngamy). The other male gamete fuses with the diploid secondary nucleus to produce the triploid primary endosperm nucleus (PEN). The two events of fertilisation is termed as double fertilisation.