I'm pretty sure the answer is B have a nice day
Answer:
the answer is C) They increase the rate of the chemical reactions involved in digestion
Explanation:
The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin. Thus, digestion of food occurs within the mouth, even before food reaches the stomach.
They have longer periods of revolution.
Atria is a large part of the heart so too big for cells; arteries & veins lead away or to the heart.
Capillaries are the smallest vascular structures that allow materials to be exchanged easily between cells.
The carbon cycles recycles caronatoms(carbon dioxide) and the nitrogen cycle recycles nitrogen.and the carbon cycle makes carbon dioxide and the carbon dioxide goes to the trees ,and the trees get the nitrogen and starts the cycle again.