Q1. The greenhouse effect is caused when
A Green trees form a canopy in the forest
B The roof is covered with green plants to keep the building cool
C Gases like carbon dioxide trap the heat of the sun in the air Correct
D Green-coloured glass or mesh is used to cover the plants
Explanation
The correct idea is that greenhouse gases such as carbon dioxide trap heat in the atmosphere. The forest canopy describes tree cover, not the atmospheric greenhouse effect. A roof covered with plants is a green-building cooling practice, not the cause of this effect. Green-coloured glass or mesh over plants refers to a physical cover used in gardening. In the passage sense, the greenhouse effect is about heat retention by gases in the air.