Title: वैकल्पिक

Text: Organic chemistry is the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds, which include not only hydrocarbons but also compounds with any number of other elements. Including hydrogen, nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur. This branch of chemistry was originally limited to compounds produced by living organisms but has been broadened to include human-made substances such as plastics. प्रत्येक पराग्राफले परीक्षण हुनेछ।

Save test: यदि तपाईं यो टाइपिङ परीक्षणलाई साझा गर्न चाहानुहुन्छ भने यो प्रयोग गर्नुहोस् (केवल प्रमाणीकृत प्रयोगकर्ताहरूको लागि)।