Tracy examines a table that lists the frictional coefficients of various pairs of surfaces. if she wants to find out which coefficient she should apply to her lab data, the best source to consult would be a) a research database. b) a university professor. c) a science news magazine. d) an introductory textbook.

A)a research database.

Explanation:

A search database is a place where you can store survey data in a structured manner and with the least possible redundancy. These data should be able to be used by different users who are seeking relevant information about the methodology that was used in a research and the results achieved by this methodology.

Based on this, if Tracy wants to find out what coefficient of friction she should apply to her laboratory data, she should look in the search databases for which coefficient of friction was used in research data similar to her research.

"a.) well–developed vascular system."