In nature,carbon is found in elemental forms as:

$(a)$ How do forests influence the following?
$(i)$ Air
$(ii)$ Soil
$(iii)$ Water
$(b)$ Is the atmosphere on Venus and Mars different from our atmosphere? How?

Following are a few organisms:
$(a)$ Lichen $(b)$ Mosses $(c)$ Mango tree $(d)$ Cactus
Which among the above can grow on stones and also help in the formation of soil? Write the mode of their action for making soil.

List any two causes of increase in concentration of $CO_{2}$ in the atmosphere.

The two forms of oxygen found in the atmosphere are

$(a)$ The temperature inside a glass enclosure is higher than that of the surroundings. Give a reason.
$(b)$ How is the above phenomenon utilized by cold countries to their advantage?
$(c)$ Name a greenhouse gas.