The correct answer is option 2: Metamorphosis. Metamorphosis is the process by which a tadpole transforms into an adult frog. During metamorphosis, the tadpole undergoes a series of physical changes. These changes include the growth of hind legs and the subsequent absorption of the tail, the development of lungs for breathing air, and the transformation of the mouth into a structure suitable for catching prey. This process typically takes a few weeks or months, depending on the species of frog. Fertilization, option 1, refers to the fusion of sperm and egg to form a zygote. Embedding, option 3, refers to the act of firmly placing something into a surrounding material. Budding, option 4, is a form of asexual reproduction in which a new organism develops as an outgrowth or bud from an existing organism.