<span>When an individual is more than a couple of meters underwater, the air pressure in the lungs is greater than the air pressure at the waters surface. If a snorkel were used, it would move the air from the lungs to the surface, making it very difficult to breath
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Well... It wouldn't be effective as it is a synthetic progestin meant to cause menstrual bleeding and ovulation... The thing is that because that would take four more weeks to happen again, so it would be ineffective.
The mini pill which is essentially the same thing and is Progestin is to be taken everyday and has a 90 effectivity rate.
Answer:
I'm pretty sure its Skeletal System
Explanation: