The purpose of the digestive system is to break down food into simple molecules that the of the body can use.
cells
enzymes
microorganisms
chemicals

The purpose of the digestive system is to break down food into simple molecules that the cells of the body can use. 

Food is broken down  into its simplest units called monomers. Proteins are broken down into amino acids, fats are broken down into fatty acids and glycerol while carbohydrates are broken down into glucose units.

Glucose is taken in by the cells of the body and through the process of cellular respiration  is used to produce the ATP, the form of energy that cells use. Cellular respiration is the process by which cells use glucose to produce energy to power their functions.

The purpose of the digestive system is to break down food into simple molecules that the cells of the body can use.

it's the cell cycle, but cytokines is when the cell divides.

theres 3 stages interphase,mitosis,and cytokines.

interphase prepares the cell for division.

mitosis is the process of dividing the cell,it has 4 parts interphase,anaphase,metaphase,and telophase.

lastly there's cytokines,that's when the cell divides into 2 daughter cells

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.