Plants can be described as eukaryotic organisms which are able to make their own food. The process by which plants make their own food is termed as photosynthesis. During photosynthesis, plants convert water and carbon dioxide into glucose and oxygen in the presence of sunlight.
The oxygen produced by the land plants accounts for half of the oxygen present in the Earth. Hence, option D is correct.
Other options are false because none of them can carry out photosynthesis.
