By acting as decomposers on dead plants and animal
Answer: Potassium-40 decays into argon gas over time.
Explanation: Potassium-argon dating is a dating method used to determine the age of sedimentary rocks by comparing the proportion of K-40 to Ar-40 in a sample of rock, and knowing the decay rate of K-40.
Potassium-40 undergoes decay following first order kinetics as given below:

<span>b.Eusthenpteron might be a common ancestor of bats and humans.
Hope this helps!
-Payshence xoxo</span>
Answer:
The correct answer will be-gas absent in primordial atmosphere (oxygen).
Explanation:
The Miller experiment was performed in 1953 to show that organic molecules can be formed from the inorganic molecules in the conditions resembling the primordial atmosphere.
Same conditions were created to the unstable atmosphere like a mixture of gases which included- methane, sulfur dioxide and hydrogen but lacked oxygen as it was absent in the primordial atmosphere.
Thus, gas absent in the primordial atmosphere (oxygen) is the correct answer.
Is size exclusion chromatography one of the choices?