Biology : Sexual Reproduction in flowering Plants

Which of the following has proved helpful in preserving pollen as fossils?

• Pollenkitt

• Cellulosic intine

• Sporopollenin

• Oil content

Pollen grains can be stored for several years in liquid nitrogen having a temperature of

• –120°C

• –80°C

• –160°C

• –196°C

Winged pollen grains are present in

• Mustard

• Cycas

• Pinus

• Mango

After double fertilisation, a mature ovule has

• I diploid and I haploid cell

• 1 diploid and I triploid cell

• 2 haploid and I triploid cell

• 1 haploid and I triploid cell

Offsets are produced by

• Meiotic divisions

• Mitotic divisions

• Parthenogenesis

• Parthenocarpy

Double fertilization is

• Fusion of two male gametes of a pollen tube with two different eggs

• Fusion of one male gamete with two polar nuclei

• Syngamy and triple fusion

• Fusion of two male gametes with one egg