Researchers conducted a controlled experiment to investigate the effect of diet on the health of beef cattle. The initial hypothesis was that an abrupt change in diet will benefit beef cattle by reducing the sizes of bacterial populations living in the digestive systems of the cattle.

In the experiment, the researchers determined the relative abundance of two bacterial species found in the rumen of cattle. The rumen is a part of the stomach that acts as a fermentation chamber in cattle and other ruminants. Shown in the table are the results from before and after an abrupt change in the cattle’s diet. Based on the results, which of the following best explains why the initial hypothesis should be revised?

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The primary differences between the before and after columns is the abundance of specific types of bacteria.

Although celluluse and starch are both carbohydrates, they are structurally different. It would be like the difference of humans switching from celery to potatoes.

Physiologically, the cattle after the change were weaker.

The pH did change between groups.