Final answer:
The evolution of biochemical pathways can occur at different speeds, depending on various factors such as environmental conditions and selective pressures. Gene duplication can contribute to the expansion of biochemical pathways.
Step-by-step explanation:
The evolution of biochemical pathways can occur at different speeds. Some pathways may have evolved quickly over time, while others may have evolved more slowly. It depends on various factors, such as the environmental conditions and the selective pressures faced by organisms. For example, gene duplication can provide the raw material for new enzymes and enzymatic functions, leading to the expansion of biochemical pathways.