An advantage to heterospory is endosporic gametophyte.
The endosporic gametophyte do permits for embryonic formation. It prompts it to have a reduced vulnerability to varying form of environments.
The second advantage that heterscopy could offer to plants is ensuring of a well apportioned nutrient filled environment.
The well apportioned nutrient filled environment is formed as a result of the megasporangium been adhered to the sporophytic plant body. This sees to promote a good formation of the embryo.
A further advantage of heterscopy is the aftermath of fertilization.
This integument is hard as it is necessary to preserve the female gametophyte and embryo.
The answer would most likely be sodium because carbon is a plants food, phosphorus is a nutrient in soil, hydrogen is air, but sodium does not have a place in a plant:)
