Answer:
Your heart changes its rate depending on the activity, so that it can carry blood to your muscles, and therefore it needs to beat stronger if you are performing some exercise, or not so strong if you are sleeping, for example.
Explanation:
Your heart is continuously beating to keep blood circulating throughout your body.
So, here it is why your heart changes its rate: Its rate changes depending on your activity level; it is lower while you are asleep and at rest and higher while you exercise to supply your muscles with enough freshly oxygenated blood to keep the functioning at a high level.
And how: depending on your activity level, your heart has to pump enough blood to your muscles. Blood carries needed oxygen and other nutrients. Muscles need more blood sugar than any other tissue especially when working hard. To supply your muscles with oxygen your heart needs to beat faster, and this builds up your heart muscles.
Newton's First law of motion: An object at rest stays at rest and an object in motion stays in motion unless acted upon by an unbalanced force.
This is also known as the law of inertia
Anyways, you feel tossed around because unbalanced forces are acting upon you while riding on a roller coaster. Hope this helps!
What? Can you explain what you're saying better?
hydrogen is essential to nuclear fusion. hydrogen is the fuel the sun burns. we don't have to burn solar energy, so there's no smoke and pollution
Answer:
d
Explanation:
D the grass will become dry and die