Morphallaxis represents a distinct mode of regeneration that involves the remodeling and repatterning of remaining cells and tissues after injury, rather than producing new cells through cell division. This process allows organisms to regenerate complete structures or organisms by rearranging and transforming existing material.

What Morphallaxis Means

• The term morphallaxis comes from Greek roots meaning “change” or “exchange,” highlighting the process of transformation within the existing tissues.

• During morphallaxis, the organism regains lost parts or even regenerates the whole organism by rearranging the pre-existing cells rather than initiating major cell proliferation or growth.

Key Features of Morphallaxis

• Regeneration without Extensive Cell Division: Morphallaxis relies on remodeling rather than new cell production. The existing cells change their position and function to regenerate missing parts.

• Typical Examples: The best-known case is Hydra, which can regenerate a complete animal from a small fragment by reorganizing its existing cells.

• Smaller, Proportional Organism: The regenerated organism is often smaller in size but proportional and fully functional.

Clarification of Options

• Option 1: Production of lost organs by division in remaining cells describes aspects of epimorphosis, not morphallaxis.

• Option 2: Re-initiation of cell division followed by repatterning is also more characteristic of epimorphosis or stem cell-mediated regeneration.

• Option 3: Production of a complete organism by a single cell relates to parthenogenesis or asexual reproduction but is not morphallaxis.

• Option 4: Movement of an organism toward a stimulus describes taxis, unrelated to regeneration.

Summary

Morphallaxis can be best defined as the production of a lost organ or organism by the reorganization and repatterning of existing cells without significant new cell division. This process contrasts with other forms of regeneration requiring new tissue growth and cell proliferation.

Final Answer:
(1) Production of lost organ by division in remaining cell is not correct in defining morphallaxis; the correct concept aligns more with remodeling. However, given the options, the closest and most accepted definition of morphallaxis aligns with reorganization without new proliferation, emphasizing existing cells’ transformation rather than division itself. Since option (1) mentions division, it is less correct for morphallaxis.

Thus, the best-fit choice from the given options considering common usage is:
(1) Production of lost organ by division in remaining cell is incorrect for morphallaxis.

But given those choices, the correct formal definition is: morphallaxis is regeneration via reorganization without new cell division (not explicitly listed). Therefore among the given options, option (1) is incorrect as a definition of morphallaxis.

If the question asks for which option defines morphallaxis, none fully matches; the best conceptual understanding is that morphallaxis involves reorganization without division (so option 1 is false).

The question seems to ask “Morphallaxis can be defined as,” and among options:
(1) Production of lost organ by division in remaining cell
(2) Re-initiation of cell division in existing cells, followed by re-patterning of those cells
(3) Production of complete organism by single cell
(4) Movement of organism toward stimulus

The correct answer consistent with morphallaxis is best described by option (2) as it mentions re-patterning and division, but morphallaxis is mostly without proliferation.

Since morphallaxis involves little or no cell division, the best matching option is none. Given the options, the closest is (2) due to inclusion of re-patterning.

Best Final Answer:
(2) Re-initiation of cell division in existing cells, followed by re-patterning of those cells
because it covers repatterning, though morphallaxis often features minimal division.