Answer: Are there any options? you either add C02 because it has run out gas or you and in minerals that also contain C02.
Explanation: you need C02 to have photosynthesis, so with a closed off lid, the gas is going to eventually run out.
note:
Gymnosperms possess several key evolutionary innovations compared to earlier groups such as the clubmosses and ferns. They produce sperm-containing pollen, which is carried through the air by the wind to the female. This innovation has freed these plants from the need for water for sexual reproduction.
