B - When many individuals of the same species are available for mating.
And
C - When the individuals live in a stable environment in which they thrive.
<span>Nuc is short for nucleus</span>
Whenever the sperm and the egg combine, it is possible for one or the other to not split properly and bring 2 of the chromosomes instead of just 1
The correct answer is: Heartburn often results when the gastroesophageal sphincter fails to close properly.
The gastroesophageal sphincter is a muscle located at the bottom of the esophagus that has to be relaxed in order to allow food to flow down into the stomach. After it contracts (tightens), the food and the stomach acid can’t flow back up into the esophagus.
When the gastroesophageal sphincter fails to close properly acid reflux occurs and causes the heartburn.
20 Amino acids is the answer
