A student placed a test tube containing a mixture of compounds into a beaker of water maintained at 30 degrees C.A chemical reaction took place and was completed in 30 minutes. A second test tube containing an equal amount of the same mixture plus substance Y was placed in the same beaker of water. The chemical reaction in the second tube was completed in less than one minute. Substance Y was most likely? an auxin an enzyme a sugar a nucleotide

Based on the information provided, the chemical reaction in the second test tube containing the mixture plus substance Y was completed much faster than in the first test tube containing only the mixture. This suggests that substance Y acted as a catalyst to speed up the reaction.<br /><br />Among the options provided, the most likely candidate for substance Y is an enzyme. Enzymes are biological catalysts that speed up chemical reactions in living organisms. They work by lowering the activation energy of a reaction, allowing it to proceed faster than it would otherwise.<br /><br />Auxins are plant hormones that regulate growth and development in plants. Sugars are organic compounds that provide energy for living organisms. Nucleotides are the building blocks of DNA and RNA. None of these substances are known to act as catalysts to speed up chemical reactions.<br /><br />Therefore, the most likely answer is that substance Y is an enzyme.