Answer:
Environmental factors can influence natural selection because they can increase or decrease the amount of genetic variation in a population.
Explanation:
Natural selection is a process that involves the survival of species through changes in the expression of their genes, making possible the process of adaptation to environmental changes. It is one of the explanations for the biological evolution of species.
The second premise, necessary for natural selection to be possible, implies the existence of a variability (genetics) of traits among individuals in a population.
The other premises of natural selection are the faculty of traits to be inheritable and that genetic variability should lead to reproductive success and survival.
- <em>The other options are not related to the process of natural selection, since it is not possible for natural selection to increase or decrease the number of chromosomes, in addition to the fact that genetic variability must be observed in a population, not in a single individual, to be considered natural selection </em>
 
        
                    
             
        
        
        
When ATP loses a phosphate, energy is released and ADP is formed
 
        
                    
             
        
        
        
Parietal cells produce gastric acid (hydrochloric acid) in response to histamine (via H2 receptors), acetylcholine (M3 receptors) and gastrin (gastrin receptors). Parietal cells contain an extensive secretory network (called canaliculi) from which the HCl is secreted by active transport into the stomach.
 
        
             
        
        
        
Answer:
pancreas: secretes digestive enzymes into the small intestine
esophagus: the place where peristalsis takes place
small intestine: area of the digestive tract where most nuturients are absorbed
stomach: area of the digestive tract that follows the esophagus
large intestine: area of the digestive tract where mostly water is absorbed
Explanation:
peristalsis: so the food can move down towards your stomach, independently of gravity
pancreas: helps your stomach become the ultimate weapon to destroy anything that gets in there with its enzymes 
small intestine: it is really really long -> more time to absorb nutrients
large intestine: like a farm of bacteria, the most exotic things that somehow made it through all the way here are finally destroyed -> also, water absorbtion: your body wants to retain as much as possible, this is how and where stool formation takes place