Final answer:
Mendel's discovery that traits are transmitted independently is known as the law of independent assortment, a fundamental principle of genetics that provides for diversity in offspring.
Step-by-step explanation:
Mendel discovered that traits are inherited independently of one another. This concept is known as the law of independent assortment. Mendel's research on pea plants revealed this principle, stating that different traits, such as color, height, or seed type, are transmitted independently during the formation of gametes, leading to a variety of genetic combinations. This independent assortment of alleles provides for a great degree of diversity in offspring, except when alleles are linked on the same chromosome. Mendel's findings were critical in disproving the then-accepted blending theory of inheritance and laid the foundation for modern genetics.