why the shelled eggs were formed instead of the aquatic egg
Dear student,
Shelled eggs were formed instead of aquatic eggs because eggs of the terrestrial animals would dry in the atmosphere therefore to protect the egg of terrestrial animals they have developed shell on the egg to survive in dry condition and to prevent from dehydration due to the presence of mineralised proteins with pore system to allow respiration. It also prevent from damage, predator and pathogen. But aquatic eggs are present in wet condition do not need shell.
Regards
Shelled eggs were formed instead of aquatic eggs because eggs of the terrestrial animals would dry in the atmosphere therefore to protect the egg of terrestrial animals they have developed shell on the egg to survive in dry condition and to prevent from dehydration due to the presence of mineralised proteins with pore system to allow respiration. It also prevent from damage, predator and pathogen. But aquatic eggs are present in wet condition do not need shell.
Regards