Which of the following statements best categorizes a challenge in microbiome research related to health and disease modulation?

A key challenge is proving that changes in the microbiome actually cause disease or health improvements, rather than merely being associated with them. Scientists must design experiments that can isolate specific microbes or microbial functions and show that manipulating them changes disease outcomes. For example, giving a probiotic that restores a missing bacterial species can reduce inflammation in mice, but showing that this effect is not due to other dietary changes requires careful controls. Thus, establishing causality, not just correlation, is the central hurdle in translating microbiome insights into therapies.