Which method of asexual reproduction occurs in $Spirogyra$?

Why are budding,fragmentation,and regeneration all considered as asexual types of reproduction? With neat diagrams,explain the process of regeneration in Planaria.

Explain how organisms create an exact copy of themselves.

In which organism does reproduction occur through binary fission?

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

Why is it that asexual reproduction produces exact copies, but sometimes minor variations are also seen in the next progeny?