There is no current consensus among biologists on the questions of how sex in Eukaryotes arose in evolution, what basic function sexual reproduction serves, and why it is maintained, given the basic two-fold cost of sex.
Excessive production of gas by bacteria is a common cause of intermittent abdominal bloating/distention. Bacteria can produce too much gas in three ways. First, the amount of gas that bacteria produce varies from individual to individual.
1 Distention of the kidney with urine. Hydronephrosis is caused by obstruction of urine outflow (for example, by a stone blocking the ureter). 2  Cystinuria is a common genetic condition that causes excess buildup of a protein, cystine, in the urine.  Nausea is an uneasiness of the stomach that often precedes vomiting.