Which of the following is without exception in angiosperms?

Explanation

b. Double fertilization is without exception in angiosperms. Double fertilization is a unique and characteristic feature of angiosperms (flowering plants) in which two fertilization events occur during the process of sexual reproduction. One sperm cell fertilizes the egg cell to form the zygote, while another sperm cell combines with two polar nuclei to form the triploid endosperm. This results in the development of both the embryo and the endosperm within the seed. Double fertilization is a defining feature of angiosperms and distinguishes them from other plant groups. Other options are explained below: a. Presence of vessels: Angiosperms indeed have vessels, which are specialized water-conducting cells found in their xylem. This is a characteristic feature distinguishing them from gymnosperms and other plant groups. b. Secondary growth: Angiosperms can undergo secondary growth, allowing them to increase in girth over time. This is achieved through the activity of lateral meristems, particularly the vascular cambium and cork cambium. c. Autotrophic nutrition: Angiosperms, like all plants, exhibit autotrophic nutrition. They produce their own food through photosynthesis, utilizing sunlight, water, and carbon dioxide to synthesize organic compounds.