An isotope of a radioactive element has half-life equal to 9 thousand years. imagine a sample that is so old that most of its radioactive atoms have decayed, leaving just 10 percent of the initial quantity of the isotope remaining. how old is the sample? (give your answer correct to at least one decimal place.)

For this problem, we use the formula for radioactive decay which is expressed as follows:

An = Aoe^-kt

where An is the amount left after time t, Ao is the initial amount and k is a constant. 

We calculate as follows:

An = Aoe^-kt
0.5 = e^-k(9000)
k = 7.7 x 10^-5

An = Aoe^-kt
.10 = e^-7.7 x 10^-5(t)
t = 29903.7 years

oof cheaters cheat because they’re lazy that’s why i cheat xd

: )

step-by-step explanation:

the answer is; biodiversity resulting from few ancestors

adaptive radiation occurs when a population is subjected to a large natural environment with spatial ecological variations. the parts of the population in the different ecologies begin to adapt to their local environments. due to non-random mating across the large populations, this causes the different populations from the large population to speciate within their local environments. they, therefore, diverge to different species sharing a common ancestor.