A certain drug has a half-life in the body of 2.5 hour. What should the interval between doses be, if the concentration of drug in the body should not fall below 45.% of its initial concentration? Round your answer to 2 significant digits.

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.