The salinity in salt marshes can vary throughout the day because
a. river flow changes throughout the day
b. the amount of salt water in a marsh depends upon ocean tides
c. daily winds and rains result in salt and fresh water mixing
d. salt water collects in the lowest elevations

What is the main difference between primary and secondary sources? a. primary sources are historical documents, and secondary sources are modern-day documents. b. primary sources are derived from museums and archives, and secondary sources are created by history students and academics. c. primary sources are found in ancient places with a rich history, and secondary sources are found in historical journals and blogs. d. primary sources are created during a particular historical era, and secondary sources are created by studying primary sources.