Leaves of $Bryophyllum$ fallen on the ground produce new plants. Why?

Length of pollen tube depends on the distance between :

Length of pollen tube depends on the distance between

What would be the ratio of chromosome number between an egg and its zygote? How is the sperm genetically different from the egg?

Offspring formed by asexual method of reproduction have greater similarity among themselves because
$(i)$ asexual reproduction involves only one parent
$(ii)$ asexual reproduction does not involve gametes
$(iii)$ asexual reproduction occurs before sexual reproduction
$(iv)$ asexual reproduction occurs after sexual reproduction

In $Rhizopus$,tubular thread-like structures bearing sporangia at their tips are called: