What is an example of Mendel’s first hypothesis regarding patterns of inheritance? What important vocabulary word do we learn in this hypothesis? Solution Gregor Johann Mendel studied the pea plant in his garden. He selected characters that were easily identifiable. He grew the plants he selected to make sure they were pure – i.e. they were pure line. A pure line is a plant that does not show any variation for the particular character under study. Based on his studies, and the careful records he maintained, Mendel proposed his first hypothesis as; Vocabulary Trait Factors Genes Alleles Homozygous Heterozygous Dominant Recessive F1.