Which of the following observations about the microbiome was important in the case?

• A. The human microbiome does not change in response to diet.
• B. Microbiomes are only found in soil environments.
• C. The diversity of gut microorganisms influences host immune responses.
• D. All microorganisms in the microbiome are pathogenic.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the concept of the human microbiome, which refers to the community of microorganisms living in and on the human body, including bacteria, viruses, fungi, and other microbes.
2. Step 2: Recognize that the microbiome is dynamic and can change in response to various factors such as diet, environment, and health status, so the statement 'The human microbiome does not change in response to diet' is incorrect.
3. Step 3: Know that microbiomes are not limited to soil environments; they exist in many habitats including the human body, so the statement 'Microbiomes are only found in soil environments' is false.
4. Step 4: Understand that not all microorganisms in the microbiome are pathogenic; many are beneficial or neutral, contributing to processes like digestion and immune system modulation, so the statement 'All microorganisms in the microbiome are pathogenic' is incorrect.
5. Step 5: Focus on the key observation that the diversity of gut microorganisms influences host immune responses, which is important because a diverse microbiome can help regulate and strengthen the immune system, making this the correct and relevant statement in the case.