A. Truncation of a word will yield more results because it opens the search to various word forms, not just one form of the word. Any record that has at least one of the words represented by the truncated term will be retrieved.
For example, immigra* will search for records containing all these word forms: immigrate, immigrated, immigrating, immigrant, immigration. Two screenshots below illustrate the difference in results with vs without truncation.
Example: Search Results without Truncation

Example: Search Results with Truncation
