Question

1. which are the catalysts of reactions in living things? a. enzymes b. lipids c. carbohydrates d. substrates 24. what changes during a chemical reaction between two compounds? a. number of atoms b. chemical bonds c. total mass d. total energy

Explanation:

For question 23, enzymes are biological catalysts that speed - up reactions in living organisms. Lipids are for energy storage and membrane formation, carbohydrates for energy supply, and substrates are what enzymes act on.
For question 24, in a chemical reaction between two compounds, chemical bonds break and form, while the number of atoms, total mass, and total energy are conserved according to the law of conservation of mass and energy.

Answer:

1. a. enzymes
2. b. chemical bonds