Indicate whether each statement is true or false: 1. Water can move either direction across the wall of the small intestine; osmotic gradients across the epithelium determine the direction of its movement.
2. Because of the osmotic gradient produced as nutrients are absorbed in the small intestine, nearly all water that enters by way of the oral cavity, stomach, or intestinal secretions is excreted.
3. Potassium, calcium, chloride, magnesium and phosphate ions all move passively through the intestinal wall of the duodenum and jejunum following positively charged sodium ions.
a. True
b. False