Answer: First blank - performing
Second blank - develop
Explanation:
Parallel structure is a situation in which the two or more phrases/clauses have the same grammatical structure. This makes a text easier to read. In this particular case, since we already have the gerund 'practicing', it will be followed by another gerund form - 'performing'. Similarly, since we have present simple tense 'acquire', the option we are going to chose is 'develop'.
The grammatically correct sentence is: Practicing regularly and performing frequently help young musicians acquire skills and develop confidence.
