Pollen germination and pollen tube growth are regulated by chemical componrnts of pollen interacting with those of the pistil.

Some reptiles have also been reported as pollinators in some plant species.

Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style.

Insects that consume pollen or nectar without bringing about pollination are called pollen/ nectar robbers.

the ovum and sperms are transported simultaneously to ampullary-isthmic junction of the cervix

the sperms are transported into cervix within 48 hrs of release of ovum in uterus

the sperms are transported into vagina just after the release of ovum in Fallopian tube

the ovum and sperms are transported simultaneously to ampullary$$-$$isthmic junction of the Fallopian tube.

It can be used for detection of Down syndrome

It is usually done when a woman is between 14-16 weeks pregnant

It is used for prenatal sex determination

It can be used for detection of Cleft palate

Intra uterine devices $$ \to $$ Increase phagocytosis of sperms, suppress sperm motility and fertilizing capacity of sperm

Barrier methods $$ \to $$ Prevent fertilization

Hormonal contraceptives $$ \to $$ Prevent/retard entry of sperm, prevent ovulation and fertilization

Vasectomy $$ \to $$ Prevents spermatogenesis