The rate at which a certain drug is eliminated by the body follows first-order kinetics, with a half life of 68 minutes. Suppose in a particular patient the concentration of this drug in the bloodstream immediately after injection is 0.12/μgmL. What will the concentration be 340 minutes later? Round your answer to 2 significant digits.

they are made of gases.

they have a spherical shape.

they make energy through fusion.

the answer is na (sodium)

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.