Question 20 Review Which event is the best example of erosion? 1. breaking apart of shale as a result of water freezing in a crack
2. dissolving of rock particles on a limestone gravestone by acid flin They 3. the deepening of a stream bed by pebbles rolling along the bottom of the stream
4. crumbling of bedrock in one area to form soil​

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.

materials water oxygen those are the things i can think of in this moment.