In animal tissue culture, “organ culture” techniques are commonly divided based on the type of medium employed. Which classification best reflects this division?

Introduction / Context:
Organ culture is a classical approach in animal cell biotechnology where small pieces of tissue are maintained in vitro so that they preserve their structural organization and differentiated function. A key way textbooks categorize organ culture is by the physical state of the nutrient support: solid (gels or clots) versus liquid (medium bathing or interface methods).

Given Data / Assumptions:

• The question asks how organ culture techniques are divided.
• Standard laboratory references describe methods using solidified matrices (for example, agar, collagen, fibrin/plasma clots) and liquid-phase systems (for example, raft or interface cultures).
• We assume routine mammalian organ culture conditions.

Concept / Approach:
Classification by medium state helps predict oxygenation, diffusion, and mechanical support. Solid matrices stabilize the explant and mimic extracellular scaffolding. Liquid systems favor exchange of nutrients and gases at a liquid–gas interface and are often rotated or rocked to improve diffusion.

Step-by-Step Solution:

Verification / Alternative check:
Protocols for organ culture of trachea, retina, or fetal tissues routinely describe agar/plasma clot (solid) and liquid–gas interface methods, confirming the two-part division.

Why Other Options Are Wrong:

Common Pitfalls:
Equating “semi-solid” with a separate overarching category; it is simply one form of solid matrix.

Final Answer:
Both solid and liquid media are used to classify organ culture methods.