Answer:
D. DNA
Step-by-step explanation:
Genetics can be defined as the scientific study of hereditary in living organisms such as humans, animals and plants.
Heredity refers to the transfer of traits (specific characteristics) from the parent of a living organism to her offspring through sexual reproduction or asexual production. Some examples of hereditary traits are dimples, tongue rolling, baldness, handedness, freckles, curly hair, color blindness, height, etc.
Deoxyribonucleic acid (DNA) is a strand of evidence which helped to provide a link in the evolution of whales from land mammals on 4 legs to a sea mammal with fins.
Basically, deoxyribonucleic acid (DNA) is an organic complex-molecular structure found in all living organisms. It comprises of genes and is essentially the foundation block of all living organisms such as humans, animals and plants.