Question

Maintaining a healthy lifestyle through diet and exercise is important, but it has no effect on the immune system. but it actually decreases the immune system. and it has been scientifically proven to boost the immune system. but it has not been proven to boost the immune system.

Answer 1

The answer is but no specific diet has been proven to boost the immune system.

Step-by-step explanation:

I just took the test.

Answer 2

Assuming this is a question and answer type situation, the best option from the list is that "it has been scientifically proven to boost the immune system" among other things.