Oestrus cycle is seen in

$A-$ Events after the formation of zygote are called post fertilization events

$R -$ In viviparous animals a young one develops out side the mother body

Which of the following are the carriers of male gametes in seed plants ?

Which of the following statements is incorrect ?
$(i)$ Bamboo species flower only once in their life time, generally after $50-100$ years and produce large number of fruits and die.
$(ii)$ In animals, the juvenile phase is followed by morphological and physiological changes prior to active reproductive behaviour.
$(iii)$ The reproductive phase is of same duration in all organisms.
$(iv)$ Juvenile phase is the period of growth between the birth of an individual till it reaches reproductive maturity.

After culturing the anther of a plant, a few diploid plants were found along with haploid plants. The diploid plants could have arisen from