Developmental biology concept — “Cellular totipotency” is best described as a property most broadly exhibited by which kingdom in practical biotechnology?

Introduction / Context:
Totipotency refers to the inherent potential of a single cell to regenerate into a complete organism. In practical tissue culture, plant somatic cells frequently display totipotency, enabling mass propagation, rescue of hybrids, and regeneration after genetic transformation.

Given Data / Assumptions:

• Plant cells can dedifferentiate and re-enter the cell cycle.
• Hormone regimes (auxin/cytokinin) guide differentiation into shoots and roots.
• Animal somatic cells are generally not totipotent (exceptions: very early embryonic cells).

Concept / Approach:
While the zygote of many organisms is totipotent by definition, the question targets practical, widely used totipotency in biotechnology. Plants uniquely and routinely express totipotency across diverse somatic tissues.

Step-by-Step Solution:

Verification / Alternative check:
Protocols for callus induction, organogenesis, and somatic embryogenesis in many crops (e.g., rice, tobacco) are standard and demonstrate totipotency.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing pluripotency/induced pluripotency with totipotency; only totipotency yields a full organism including extra-embryonic tissues in animals.

Final Answer:
Plants (most somatic cells can regenerate a whole plant under the right conditions).