Answer: The rock is 2000785 years old.
Explanation:
Expression for rate law for first order kinetics is given by:

where,
k = rate constant
t = age of sample
a = initial amount of the reactant = 800
x = amount of daughter isotope = 600
a - x = amount left after decay process = amount of parent isotope = (800-600) = 200
Half life is the amount of time taken by a radioactive material to decay to half of its original value.




The rock is 2000785 years old.
It depends on the mass of the ice,temperature around it and latent heat energy required to melt the ice.
However the furthest a ice berg can travel is estimately 32-40°n/s
The answer is: [A]: "fresh water" .
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Answer:
78 percent - nitrogen
21percent- oxygen
absorbs ultraviolet-ozonosphere
atmospheric weather-stratosphere
starts seven miles -troposphere
layer composed 0f layers- thermosphere
important fr radio wave-ionosphrere
trapping of heat- green house effect