Review the images and text about stages 13 (about 32 days) and 23 (about 53-58 days), and compare the limb development at these stages.

Answer:

At stage 13, all four limb buds are present, and the upper limb buds resemble flippers. By stage 23, the upper limbs have well-formed arms, elbows, wrists, and fingers, while the lower limbs have well-formed feet, toes, and knees.