Premineralization.
Permineralization
yes
Cranial bones contain air spaces. These air spaces are known as skeletal pneumaticity. Bird bones are all filled with air spaces.
Vacoules
Aquatic plants.
Permineralization
sea floor spreading
the bones are filled with bone marrow
Birds.
Saturated
Do you mean an aquifer
yes
The level at which all spaces inside underground rock are filled with water is called the water table.
The fluid filled spaces in the brain are called ventricles. The fluid is called cerebrospinal fluid
Cranial bones contain air spaces. These air spaces are known as skeletal pneumaticity. Bird bones are all filled with air spaces.
Vacoules
Aquatic plants.