12. Cell to cell communication is important in development of an organism. The ability of cells to respond to a specific inductive signal is called
(1) Regional specificity of induction
(2) Competence
(3) Juxtracrine signalling
(4) Instructive interaction

Cell-to-cell communication is vital in orchestrating the complex process of organismal development. One important aspect of this communication is the ability of cells to respond to signals produced by neighboring cells, guiding their fate and differentiation. This specific ability of cells to recognize and respond appropriately to inductive signals is referred to as competence.

Competence determines whether a cell is capable of interpreting and reacting to an inductive signal fully, thus making it responsive to instructions that influence its developmental trajectory. Cells that lack competence to a particular signal will not respond even if the signal is present. This concept explains why certain tissues can induce specific responses in some cells but not others.

Inductive signals can be conveyed via various mechanisms, including direct cell contact (juxtacrine signaling), diffusible molecular signals, or extracellular matrix interactions. However, the critical factor is the target cell’s competence to receive and act on the signal.

In summary:

• Competence is the ability of a cell to respond to a specific inductive signal.

• It is essential for correct tissue differentiation and organ formation during development.

• Without competence, cells cannot be induced properly, even if inductive signals are present.

• Competence works hand-in-hand with induction to ensure developmental precision.

Therefore, the correct answer to the question about the ability of cells to respond to a specific inductive signal is:

(2) Competence