Answer:
Genes
Step-by-step explanation:
Gregor Mendel discovered in his experiments that a factor determined the physical characteristics of an organism. This factor is called a gene. A gene is the molecular unit of heredity in a living organism.
Genes are segments of DNA that holds the information needed to build and maintain an organism and pass genetic traits to offspring. The trait of an organism, which refers to the physical characteristics of an organism, are passed from parents to offsprings via genes. The genes also contain variant forms called ALLELE that determines which trait an organism will possess.