Final answer:
Reconstructing the whole organism from a fragment is not possible in complex multicellular organisms due to the presence of different types of cells, the regulated developmental process, and the intricate physiological systems.
Step-by-step explanation:
Reconstructing the whole organism from a fragment is not possible in complex multicellular organisms due to several reasons.
Firstly, multicellular organisms consist of different types of cells that are organized into tissues, organs, and systems. Each cell has specific functions and interacts with other cells and tissues in a coordinated manner. Therefore, a single fragment does not contain all the necessary cells and structures to form a complete organism.
Secondly, complex multicellular organisms undergo a highly regulated and controlled developmental process. The development of an organism involves the activation, inactivation, and coordination of numerous genes and signaling pathways. A single fragment may not have the complete genetic information or the proper signaling cues to initiate and guide the development of all the necessary cell types and structures.
Lastly, complex multicellular organisms have intricate physiological systems, such as circulatory, respiratory, and nervous systems, which require the integration of multiple organs and tissues. A fragment of an organism will lack the functional integration necessary for the proper functioning of these systems.