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:

The answer is; C
Plasmids are conferred through horizontal gene transfer in bacteria. The ‘male’ bacteria develops a structure called pili that then attaches to the ‘female’ bacteria. It then transfers it’s replicated plasmid to the ‘female’ bacteria in a process called conjugation. This bacteria will hence have desirable traits that are coded for by the transferred genetic material ,such as antibiotic resistance, after a process called recombination.