Which statement best summarizes gregor mendel's contribution to science?
a, mendel studied the pea plants he grew in his garden.
b, mendel found evidence that there are two factors for each trait.
c, mendel coined the word genes to describe inherited traits.
d, mendel formulated a hypothesis and then tested it.

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 a. primary sources are historical documents, and secondary sources are modern-day documents.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.