What types of skeletal changes occurred during whale evolution?

The skeletal system of whale evolved from being long to short with modified paddle like limbs and longer tails.

Explanation:

The whales were earlier terrestrial animals. The first whale on earth known as Pakicetus lived on lands and thus  have teeth like carnivores and a long skull. Later on the whales shifted their habitat from land to water and with this their bony structure also evolved. They now have short legs which more or less resembles paddle. Also its tail became long. The pelvic segregated from backbone and became short.

brown

explanation:

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.