3. Scientists hypothesize that life evolved from chemical reactions of simple inorganic molecules into more complex compounds. The following example demonstrates how simple compounds can lead to the formation of a sugar precursor required to form RNA building blocks. formaldehyde +HCN+ phosphate +CO aldol addition A ribose-2,4-diphosphate a. Draw arrow-pushing mechanism for the formation of A from the two aldehydes under basic conditions. b. Identify the compound that reacts with A to form ribose-2,4-diphosphate. Draw its structure