You are viewing a vessel through the microscope and note the presence of valves. In what direction would blood flowing as it moves through this vessel

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.

allowed for the prediction of the properties of missing elements.

mass and weight are closely related because mass affects the weight of an object experiencing the effects of gravity. weight is the measure of the force of gravity on an objects's mass, while mass is the measure of how much matter there is in an object.