I think this is what you are referring to.
Hope this helps.
Answer:
answer is 2 for both cuz they both have the 2 subscript next to hydrogen
Answer:
There are many ways.
Explanation:
Humans have a combined respiratory and circulatory system, whereas insects do not. In humans, the air is brought in through the mouth/nose, through the windpipe, and into the lungs, the oxygen is absorbed into the bloodstream where it can be transported to muscles and organs. However, insects take in air through tiny holes in their thorax and abdomen. These are called spiracles. The oxygen is stored in many dorsal air sacs to be used. Then carbon dioxide is expelled through the spiracles.
The three major types of pollution are air pollution, water pollution, and land pollution. Sometimes, air pollution is visible. A person can see dark smoke pour from the exhaust pipes of large trucks or factories, for example. More often, however, air pollution is invisible.
