Answer: Option A and B.
Pelvis and spinal column.
Explanation:
Evolutionary changes Is the changes in heritable characteristics of a population over generations. The evolutionary changes that led to human upright walking is from changes in pelvis and spinal column. The pelvis is an important structure that play a crucial role in bipedal locomotion ( walking on two legs) and thermoregulation. The alteration in shape of pelvis I.e it is short and squat make the hip joint and vertebral column closer which provide a stable support while walking upright. The spinal column or backbone is attached from the center of the brain downward, it provide support for the body while walking upright, standing or bending without causing damage to the spinal cord.
