CBSE Class 9 Answered

The smoke from the incense stick moves up with the hot rising air, when the incense stick is placed a little above the candle.

As this hot air moves up, cold air from nearby area moves in towards the candle. This can be shown by holding the incense stick a little away on one side of the beaker. The smoke will move horizontally and then downwards into the beaker.

The major component of the atmosphere of Venus and Mars is carbon dioxide.