Question

Formation of whole body from a fragment is
A. Morphallaxis
B. Epimorphosis
C. Epigenesis
D. Auxetic growth

Answer 1

Regeneration is the natural process of replacing or restoring damaged or missing cells, tissues, organs, and even entire body parts to full function in plants and animals. There are two types of regeneration- morphallaxis and epimorphosis.

Complete step by step answer: Morphallaxis: Morphallaxis is the regeneration of specific tissue in a variety of organisms due to loss or death of the existing tissue. Morphallaxis is observed in hydra where a new organism is formed from a fragment. The notable feature of morphallaxis is that a large majority of regenerated tissue comes from already-present tissue in the organism.
Epimorphosis: Epimorphosis is defined as the regeneration of a specific part of an organism in a way that
involves extensive cell proliferation of somatic stem cells, dedifferentiation, and reformation, as
well as blastema formation. It is observed in salamanders and lizards where a new limb can be regenerated after a wound. The amputation is sensed by a large number of somatic stem cells, that migrate to the wound meanwhile they increase their division rate. The wound blastemal (a white region) forms and the blastemal cells proliferate to re-generate the lost tissues.
Epigenesis: It is the process by which plants, animals, and fungi develop from seed, spore, or egg through a sequence of steps in which cells differentiate and organs form.
Auxetic growth: Auxesis refers to growth from an increase in cell size rather than an increase in the number of cells. Auxetic growth occurs in certain tissues, such as muscle, of the higher animals as well as in some organisms, such as nematodes, tunicates, and rotifers. In plant physiology, an auxetic substance will tend to increase cell growth without any cell division. Auxins are auxetic plant hormones.
So, the answer is A, i.e., Morphallaxis

Note: In morphallaxis the majority of the regeneration comes from reorganization or exchange, while in epimorphosis the majority of the regeneration comes from cellular differentiation. In morphallaxis, a whole new organism can be formed whereas in epimorphosis a whole new organism does not take place.