What are the reasons why plants can get along without respiratory organs?
a. Each plant part takes care of its own gas exchange needs. There is very little transport of gases from one plant part to another.
b. Plants do not present great demands for gaseous exchange, root, stem and leaves respire at rates far lower than animals do.
c. The distance that gases must diffuse even in large, bulky plants is not great.

Options

A. a and b
B. a and c
C. c and a
D. a, b and c

Answer

### Step-by-Step Solution:

1. **Understanding Plant Respiration**:
- Plants do not have specialized respiratory organs like animals (e.g., lungs in humans or gills in fish). Instead, they rely on their structure for gas exchange.

2. **Reason A - Self-Sufficiency in Gas Exchange**:
- Each part of the plant (roots, stems, leaves) is capable of handling its own gas exchange needs. This means that they can absorb oxygen and release carbon dioxide independently.
- Additionally, there is minimal transport of gases between different parts of the plant. This self-sufficiency allows plants to function without a centralized respiratory system.

3. **Reason B - Lower Demand for Gas Exchange**:
- Plants have a lower metabolic rate compared to animals, which means they do not require as much oxygen for respiration.
- The rates at which roots, stems, and leaves respire are significantly lower than those of animals, reducing the overall demand for gas exchange.

4. **Reason C - Short Diffusion Distances**:
- Even in larger plants, the distances that gases need to diffuse are relatively short.
- The structure of plants allows for efficient diffusion of gases through their tissues, making it unnecessary to have specialized respiratory organs.

5. **Conclusion**:
- The combination of self-sufficient gas exchange, lower metabolic demands, and short diffusion distances allows plants to thrive without specialized respiratory organs.