Rhizobium cannot make its own food. It lives in the roots of peas, moong, beans and other legumes. It obtains its nutrients from these plants and also gets shelter. In return, they help the plant to fix atmospheric nitrogen.

Green plants perform photosynthesis in the presence of sunlight and chlorophyll. This process requires carbon dioxide and water to produce glucose. This simple sugar is a carbohydrate. Oxygen is released as a byproduct during this process.

Carbohydrates are made of carbon, hydrogen and oxygen atoms. These atoms are arranged together in an specific order to form carbohydrates.

Green plants are called producers or autotrophs as they make their own food through the process of photosynthesis. Leaves prepare food through this process. So, they are called the food factories or the kitchen of the plants. 

Rhizobium bacteria thriving in the root nodules of leguminous plants are capable of nitrogen fixation. They are able to convert atmospheric nitrogen to the form usable by plants. 

Statement: 1 Mark
Explanation: 1 Mark
This statement is false.
Autotrophs only account for the green plants in the world. Since there are so many non-green plants in the world, it would be wrong to say that all plants are autotrophs. 
Many plants like the pitcher plant and Venus flytrap are partly autotrophic and partly heterotrophic. Since they grow in nitrogen-deficient soil they trap and digest insects to meet their nitrogen requirements. Some plants alike Cuscuta are completely non-green and are parasitic in nature.