Which method of asexual reproduction is observed in $Spirogyra$?

The ability of a cell to divide into several cells during reproduction in $Plasmodium$ is called

$(a)$ Identify the asexual method of reproduction in each of the following organisms:
$(i)$ Rose
$(ii)$ Yeast
$(iii)$ Planaria
$(b)$ What is fragmentation? Name a multicellular organism which reproduces by this method.

Name the type of asexual reproduction in:
$(a)$ Planaria
$(b)$ Rhizopus
$(c)$ Spirogyra
$(d)$ Hydra

$A$ simple multicellular animal that has tentacles and lives in freshwater. Which of the following asexual methods of reproduction does it use?

Give an advantage of vegetative propagation.