Just as totally relaxed actors or musicians aren’t likely to perform at the top of their potential, speakers think more rapidly and express themselves more energetically when they experience .

helpful speech anxiety    

Explanation:

Speech anxiety: In abnormal psychology, the term "speech anxiety" is described as a condition or situation in which an individual or speaker experiences 'nervousness' during or/and before a specific presentation.

Symptoms of "speech anxiety" involves a dry throat, memory loss, sweating palms, a shaky voice, difficulty breathing, etc. These symptoms are often hard to analyze or predict by the person dealing with it.

In the question above, the given statement signifies helpful speech anxiety.

i believe

clean air is essential for health and survival

clean air provides nitrogen gas for plant respiration

clean air supplies oxygen that enables living organisms to breathe

hope this

i am brianly

sorry if this doesn't