Tissues and organs contribute to the complexity of reproduction in multi-cellular organisms by requiring more sophisticated methods than simple cell-by-cell division. These structures need to be maintained in specific arrangements during reproduction.

The level of organization in multi-cellular organisms involves specialized cells forming tissues, and tissues organizing into organs, creating a structured and non-random arrangement.

Simple cell-by-cell division is impractical for many multi-cellular organisms due to their higher level of organization. These organisms have specialized cells organized into tissues, which are further organized into organs.

Spirogyra achieves reproduction by breaking up into smaller pieces upon maturation, and these fragments grow into new individuals.

The level of organization in the bodies of unicellular organisms varies, with some like Amoeba showing relatively less organization, while others like Leishmania exhibit more defined structures that influence the orientation of cell division.

Plasmodium, the malarial parasite, divides into many daughter cells simultaneously through multiple fission, contributing to the rapid proliferation of the parasite within host cells.

In Leishmania, binary fission occurs in a definite orientation in relation to the whip-like structure at one end of the cell, indicating a specific organization during division.

Unlike many bacteria and protozoa that simply split into two equal halves, Amoeba exhibits cell division where the splitting of cells can occur in any plane.

The whip-like structure in Leishmania may play a role in determining the orientation of binary fission, providing organization during cell division.