Read the passage and answer the question. The Class 8 group visited the solar park at Bhadla. In order that the panels stay cool, workers wash them before noon. Meanwhile, a technician explains how the inverters work. Many a visitor has asked about storage batteries. Ten kilometres is a long walk around the rows. The news of the trip was posted on the board. Consequently, several parents volunteered as escorts. "Many a visitor has asked" is correct because: