Question: 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.

In stage 13, all four limb buds are present. In stage 13, the upper limb buds resemble flippers. In stage 23, the upper limb shows well-formed arm, elbow, wrist, and fingers. In stage 23, the lower limb shows well-formed toes, feet, and knees.

n stage 13, all four limb buds are present. In stage 13, the upper limb buds resemble flippers. In stage 23, the upper limb shows well-formed arm, elbow, wrist, and fingers. In stage 23, the lower limb shows well-formed toes, feet, and knees.

Explanation:

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.