Ability to give rise to a new individual entity from body parts is

The correct option is Regeneration.

Step-by-step Explanation:

1. Understanding Regeneration:
Regeneration is the biological process by which certain organisms can regrow lost, damaged, or severed body parts. In simple multicellular organisms such as Planaria (flatworms) and Hydra, if the body is cut or broken into multiple pieces, many of these individual pieces can grow and develop into complete, fully functional new individual entities. This is made possible by specialized cells that rapidly proliferate and differentiate into various cell types and tissues to reconstruct the missing body parts.

2. Why the other options are incorrect:
• Reproduction: This is a general, overarching term for the biological process by which new offspring are produced. It does not specifically describe the mechanism of growing an entire organism from cut body parts.
• Fragmentation: Although similar, fragmentation occurs when a multicellular organism naturally breaks into pieces upon reaching maturity, and each piece grows into a new organism (as seen in algae like Spirogyra). It is a standard reproductive method and does not rely on complex regenerative responses to accidental injury or division.
• Fission: This is a method of asexual reproduction in unicellular organisms (such as Amoeba or bacteria) where a single cell splits to form two or more new cells. It does not involve multicellular body parts.

Therefore, the ability to give rise to a new individual entity from severed or broken body parts is specifically referred to as Regeneration.