Gregor Mendel studied pea plants because they were a good model system to understand how traits are inherited across generations. Pea plants have several useful qualities for experimentation: they are easy to grow, fast- growing, can be cross-pollinated by hand to control fertilization, and they have visible, distinct traits with only two forms (such as tall vs. short height, smooth vs. wrinkled seeds, and purple vs. white flowers). These characteristics made it easier for Mendel to observe patterns of inheritance clearly. Additionally, pea plants can self-pollinate, allowing Mendel to establish pure-breeding lines to track specific traits reliably over generations. This enabled him to discover fundamental principles of heredity such as the laws of segregation and independent assortment.