How is the embryo protected egg?

1. Shell: The most visible and obvious layer, the shell provides a rigid outer protection. It's made of calcium carbonate, which is strong and protects against physical damage and predators.

2. Shell Membranes: Beneath the shell are two membranes called the inner and outer shell membranes. These are semi-permeable, meaning they allow some gases and liquids to pass through while preventing others. This helps regulate gas exchange, allowing oxygen in and carbon dioxide out, and also helps retain moisture.

3. Albumen (Egg White): This clear, viscous fluid surrounds the yolk and embryo. It acts as a cushion, protecting the embryo from shocks and vibrations. It also provides water and protein for the developing embryo.

4. Yolk: This is the main food source for the embryo. It's rich in lipids (fats), proteins, vitamins, and minerals. The yolk also contains a special structure called the germinal disc, which contains the genetic material of the embryo.

5. Chalaza: These twisted strands of albumen attach to the yolk and help keep it centered in the egg. This ensures that the embryo is always in contact with the yolk, providing it with food.

6. Air Cell: A small pocket of air forms at the blunt end of the egg. This air cell provides oxygen for the developing embryo and allows for expansion as the embryo grows.

These layers work together to create a safe and nurturing environment for the embryo until it's ready to hatch.