the main function of this macromolecule is to: jobs your cells such as building and breaking down molecules. A) carbohydrates
B) lipids
C) nucleic acids
D) proteins

the answer is c) an oak tree

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.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.