Increasing naturally increases serotonin in the brain.

There are a lot of factors that can increase serotonin in the brain. For example increasing exercise, sunlight or vitamin B6 could all create a natural  increase of serotonin. serotonin is also greatly affected by stress levels so one could say that increased relaxation would increase serotonin.

Ifound this on google “here are some features of the alveoli that allow this: they give the lungs a really big surface area. they have moist, thin walls (just one cell thick) they have a lot of tiny blood vessels called capillaries.for more information go to the website below › bitesize › guidesi hope this you for what your looking for. can you plz mark me brainliest?