Because its air we cant see it thats why its clear because it would be scary if we were able to see air! :)
The answer to your question is A
Long-term activation of your body’s stress response system, along with prolonged exposure to cortisol and other stress hormones, puts you at risk for health troubles. These health issues include digestive problems, anxiety, headaches, depression, sleep problems, weight gain, memory and concentration issues, high blood pressure, heart disease and strokes. Being stressed also lowers your threshold for pain, causing more extreme discomfort from the previous affects.
