The radioactive element carbon-14 has a half-life of 5750 years. a scientist determined that the bones from a mastodon had lost 69.4% of their carbon-14. how old were the bones at the time they were discovered?

9595.8 years

Explanation:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

Expression for rate law for first order kinetics is given by:

where,

k = rate constant  

t = age of sample

a = let initial amount of the reactant  =100

x = amount decomposed or lost =

a - x = amount left after decay process= (100-69.4)= 30.6

Putting in the values:

Thus the bones were 9595.8 years old.

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.