7. What causes high and low tides? O A. The series of regular lunar eclipses
O B. The frictional coefficient of water
O C. The gravitational pull of the sun and the moon
O D. The rotation of the earth on its axis

the correct answer is option D

Answer is C

Explanation:

The moon and sun have their own gravitational pulls that indeed cause high and low tides. If you can see the moon over you at a beach for say, then the tides would be high, if there is no moon, then the tides are low

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.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.