Solution :
Definition :
“A fragment of the parent becomes a new being during the fragmentation process.”
Multicellular organisms can divide or reproduce by fragmentation.
But, it cannot be used by all multi-cellular organisms.
Organisms with complex structures cannot undergo cell-by-cell division.
This is because, in complex multicellular organisms, each set of cells has specialized functions.
These specialized cells are organized as tissues and are placed in organs.
Organs are placed in different positions in the body.

Fragmentation in Spirogyra
i) When an organism reaches maturity, fragmentation, a form of asexual reproduction, occurs, where in the organism just splits into separate parts.
ii) These individual small pieces then grow to form a new organism e.g., Spirogyra.