The answer would be the first one :)
Physical activity causes an increase in your heart rate. Your body have to change the way it behaves so you don’t get ill or sick or pass out during physical exertion
The sky is blue because blue<span> light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. </span>Blue<span> is scattered more than other colors because it travels in shorter and smaller waves. This is why we see a </span>blue sky most<span> of the time. Hope this helps!</span>