A rock contains a radioactive isotope that decays to half of its original amount in 5 million years. When this rock formed, it was made up of 100%
of the radioactive isotope, and 0% of the new element that it decays
If you find this rock and analyze it, and find that it contains only 50% of the
radioactive isotope and 50% of the new element, how old must this rock
be? *

1) 2.5 millon years

2) 10 million years

3) 5 million years

4) 15 million years

relative humidity, temperature and dew point -- are bound together in the mathematical relationship below. relative humidity changes when temperatures change. because warm air can hold more water vapor than cool air, relative humidity falls when the temperature rises if no moisture is added to the air. so i would say a

the answer is d. chordata

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.