Title: वैकल्पिक

Text: There is, however, another problem that confronts evolutionary theory. There are over 100 amino acids, but only 20 are needed for life's proteins. Moreover, they come in two shapes: Some of the molecules are "right-handed" and others are "left-handed". And there is no known reason why either shape should be preferred in living things. Yet, of the 20 amino acids used in producing life's proteins, all are left-handed! प्रत्येक पराग्राफले परीक्षण हुनेछ।

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