In the egg of bird, shell and shell membranes are

Options

A. Permeable to `O_(2) "and" CO_(2)`
B. Permeable to water only
C. Permeable to air only
D. Non-permeable

Explanation

To answer the question regarding the permeability of the shell and shell membranes in the eggs of birds, let's break down the information step by step:

### Step-by-Step Solution:

1. **Understanding Bird Eggs**: Bird eggs, known as cladoic eggs, have a specific structure that allows for gas exchange.

2. **Composition of the Shell**: The shell of a bird's egg is primarily made of calcium carbonate. This composition is crucial for the egg's strength and protection.

3. **Permeability of the Shell**: The shell and the shell membranes of bird eggs are permeable to gases, specifically oxygen (O2) and carbon dioxide (CO2). This permeability is essential for the developing embryo to receive oxygen and expel carbon dioxide during the incubation period.

4. **Water Permeability**: While the shell is permeable to gases, it is not significantly permeable to water. This is important to prevent the egg from losing moisture while still allowing for gas exchange.

5. **Conclusion**: Given the options provided in the question, the correct answer is that the shell and shell membranes of bird eggs are permeable to O2 and CO2.

### Final Answer:
The shell and shell membranes of bird eggs are permeable to O2 and CO2.

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