Karen knows that trees use energy from the sun to make food. she wants to plant several trees in her backyard, but she is worried that she will use up the sun's energy. is karen correct?

Karen is NOT correct. This is because the sun's energy is a renewable resource. This means that its  use is sustainable hence it is a substance of economic value that can be replaced or replenished in the same or less amount of time as it takes to draw the supply down. Though the sun is a finite resource,  it cannot be depleted within human timescale.

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.

its temperature is increasing. this causes molecular vibrations to increase.