1. what is the usual cause of a harmful increase in the nutrients in a freshwater lake?
a. global warming
b. runoff of fertilizers and sewage
c. loss of biodiversity
d. seasonal variations in rainfall.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

c. establishing proper sleep hygiene

answer///systemic;