(i) Both A and R are correct and R is the correct explanation of A.

Explanation:Sun is the major source of light energy and it is required by all the organism for sustaining their lives. The Sun radiates its rays which enter into the Earth’s atmosphere but due to the presence of ozone, it doesn’t able to escape. This results in the increase of the temperature inside the Earth. This is known as Greenhouse Effect. In the greenhouses the factors which regulate or drive the normal physiological processes/functioning of the plants get accelerated. Temperature (controlled by heaters or fans etc), humidity, soil aeration, irrigation, fertility levels and controlled light amounts are required for the optimum growth of plants. Therefore, plants are able to grow properly and yield more amount of biomass due to the availability of these safe and protected conditions.

The greenhouses are generally transparent buildings or big rooms which are made up of glass (PMMA/ acrylic glass)or green glassor plastic (polyethylene film) or polycarbonate material multiwall sheets which are used to trap the radiations coming from the Sun. Green glass is composed of chrome oxide (different concentrations give variations in green color). Thus, to give a typical green color, they are composed of green glass.