Which of the following concepts refers to the biological distinction between males and females?

sex
primary sex characteristics
gender
gender roles

Sex.

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answer: all : )

explanation:

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.