Which of the following substrates is expected to support the slowest growth in yeast based on its availability for respiration?

Sorbose is expected to support the slowest growth in yeast primarily because it is not a commonly utilized sugar compared to the others listed. Yeast, particularly Saccharomyces cerevisiae, typically prefers glucose due to its straightforward metabolic pathway, which allows for immediate energy production.

While fructose and galactose can also be metabolized by yeast, the pathways to convert these sugars into usable energy are less direct than that of glucose. Sorbose, on the other hand, may have limited or inefficient metabolic pathways available in certain yeast strains, leading to lower growth rates. The yeast may need more time and resources to convert sorbose into a form it can easily respire. Therefore, the unavailability or inefficiency of respiration pathways for sorbose makes it the least effective choice for promoting growth in yeast compared to the others.