Which of the following is the most resistant material in pollen grain
Sporopollenin
Intine
Exine
Certicle
The pollen tube usually enters the embryo sac
through one of the synergids
by directly penetrating the egg
between one synergid and central cell
by knocking off the antipodal cells.
Phytochrome occurs in two forms. In which form it promotes the germination of seeds of some species ?
Pfr forms
Pr forms
Both forms
None of these
Assertion: Coconut tree is distributed in coastal areas over a large part of the world.
Reason: Coconut fruit can float and gel dispersed over thousands of kilometers before losing viability.
If both Assertion and Reason are true and Reason is the correct explanation of Assertion
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
If Assertion is true but Reason is false
If both Assertion and Reason are false.
Double fertilization means
fusion of nucleus of male gamete with the egg nucleus
fusion of two polar nuclei
fusion of sperm nucleus with secondary nucleus
fusion of one sperm nucleus with nucleus and fusion of other sperm nucleus with secondary nucleus
The formation of embryo without fusion of gametes is termed as :
apospory
isogamy
apogamy
syngamy
The plant part which consists of two generations, one within the other, is
genninated pollen grain
embryo
unfertilized ovule
seed
If the pollen tube enters the ovule through funiculus, the phenomenon is known as
porogamy
chalazogamy
mesogamy
heterogamy
Assertion: Insects visit flowers to gather honey.
Reason: Attraction of flowers prevents the insects from damaging other parts of the plant.
If both Assertion and Reason are true and Reason is the correct explanation of Assertion
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
If Assertion is true but Reason is false
If both Assertion and Reason are false.