What is the theory which offers scientific explanation for both the unity and diversity of life

Would really appreciate it, i have an idea but not completely sure

Need an answer asap 45 points and brainlest to the first person to answer why do scientific theories, such as biological and chemical evolution, represent the strongest explanation of the changes observed in the fossil record. must be in sentence form how can scientific theories on evolution and the fossil record change over time? must be in sentence form

26 a medida que cambia el clima, ¿qué tipo de reproducción más probablemente de a una especie mayores posibilidades de supervivencia?