Lia looked out the window and saw birds at a feeder. How was Lia able to see the birds? Light reflected off the birds and traveled to Lia's eye.
Lia's eye made light that traveled to the birds.
Beams of light traveled back and forth between the birds and Lia's eye.
The birds produced beams of light that traveled to Lia's eye.

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up

the design of a ski jumping suit involves a trade-off between giving the skiers lift to get higher jumps and ensuring the skier does not face a lot of drag before the jump itself. an expansive suit may to lift the skier higher, but at the same time, it will also increase the air resistance. higher air resistance as the skier goes down the slope limits the speed of the jump. a big suit also increases the risk of losing balance or control, especially if there's a strong gust of wind. while technologically enhanced suits a lot, clothing is not the only factor in a ski jumper’s success. gathering speed while skiing down the slope, ensuring good speed on the ramp, and maintaining good body posture and form in the air all contribute to a ski jumper's success.