Why must eggs which take longer to hatch be larger?

Eggs that take longer to hatch must be larger to provide sufficient nutrients and energy for the developing embryo. A larger egg contains more yolk, which supplies the necessary resources for growth during the extended incubation period. Additionally, larger eggs often have thicker shells, offering better protection for the embryo as it develops over a longer timeframe. This balance ensures that the embryo can survive and thrive until it is ready to hatch.