Answer:
The rock is 3.75 billion years ago.
Explanation:
Given that:
Half life = 1.25 billion years
1 billion years = 10⁹ years
So,
Half life = 1.25 × 10⁹ years

Where, k is rate constant
So,


The rate constant, k = 5.5452 × 10⁻¹⁰ years⁻¹
Initial amount [A₀] = 80 micrograms
Final amount
= 10 micrograms
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
So,





So,
<u>The rock is 3.75 billion years ago.</u>
The border line is a thin black line
I believe the correct answers are Head of State and Chief Justice. hope this helps, have an amazing day :)
The correct answer is participant modeling.
Participant modeling refers to a psychotherapy technique in which a therapist models or demonstrates to their client how to respond to a fear provoking stimulus in gradual steps. After this, the client is encouraged to imitate the therapist's modeled behavior step-by-step so that he or she can learn how to cope with the fear provoking stimulus when faced with it outside a therapy setting.
Benefits- Keep in touch, stay informed
Negatives- Risk of cyber bullying, risk becoming addicted, procrastination
You could miss out on relationships, times to hang out with others, etc