Answer:
As air pressure decreases oxygen continues to account for about 21% of the gasses in the air as it does at sea level. But, there is less oxygen because there is less of all of the air's gasses
Answer:
Before answer this question, you need to know what is the half-life of a compound, the term half-life is defined as the time it takes for one-half of the atoms of a radioactive material to disintegrate. Knowing this you know that has passed half of the half-time, so you should probably have 25% of the original amount of 235U. This problem may be tricky because it says half of the time to reach the half-time, but 50% of the compound will be present in 750 million years after the death of the specimen.
Vaccine is preventing the infection.
Antiviral is a medicine taken after infection
Sub and super
Pre and post
Bene and mal
