If the sealed glass is permeable to sunlight or to transfer of heat will be an open system, but if the sealed glass is a thermic glass and doesn't allow exchange of heat and exchange of solar energy (for example a mirrored glass that reflect the sunlight) and the terrarium is not exchanging energy with the surroundings will be a closed system. It is a question that doesn't specify too many details about the system in the study. It is hard to give a final answer without making some assumptions.
The answer would be Rocks, metals, hydrogen compounds, hydrogen and helium, all in gaseous form.
The correct answer is neon
They are used to pass food to the oral mouth at the center, and can attach to surfaces.
