1. When it comes to crickets, what does fitness mean?

When it comes to crickets, fitness means one's reproduction in producing as many offspring as possible, so the chances of their offspring living are higher. In addition, the passing on their genes is the most important for their offspring's evolution.

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.

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