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.
Varuable, In algebra, a symbol (usually a letter) standing in for an unknown numerical value in an equation :)
Troposphere is the highest layer of the atmosphere and touches space
Startophere is where stratus clouds form up high in the sky
The Mesosphere is the third layer you need to know and it’s low density ...yo?
Thermosphere we’re getting closer and closer to earth
Exoshpere were airplanes are high, buckle up it’s time to fly