How would the contractile vacuole of a freshwater amoeba respond if the organism was placed in seawater? a) with more contractions b) with fewer contractions c) the contractions would suddenly cease d) with the same frequency of contractions

 A. more contraction

Osmoregulation is  a process in which water content of the protoplasm of the cell are controlled. In amoeba the water content in the protoplasm is controlled by contractile vacuole. The protoplasm of the amoeba remains concentrated than the surrounding water. The water enters the protoplasm by osmosis through semi- permeable membrane. The excess of water is expelled out by contractile vacuole. Most seawater amoeba protoplasm lacks contractile vacuole because the salt concentration inside the protoplasm is same as that of the surrounding water so that no more water could enter inside the protoplasm which may result in rapture of the cell. When freshwater amoeba is placed in seawater than seawater being hypertonic the water will flow out of the cell the contractile vacuole will become more contracting to release water and the cell will shrivel up. 

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.