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>
Answer:
Option D, The end of the great Texas cattle drives, is the right answer.
Explanation:
The Spanish settlers were the first to bring the longhorn cattle in North America. During the course of time, Texas became home to millions of longhorn cattle. The cattle ranchers of the area wanted to sell them in the markets of East and North for the reason the demand was high and the supply was low. Such cattle drives came to an end in the decade of 1880s for various reasons. The invention of barbed wire, the expansion of railroads and too many cattle grazed on the crowded ranges and thus there was not enough grass to feed them all, were some of the significant reasons.
Answer:
A
Explanation:
It was the mass murder of Jews
A the answer is a because like i just know because i’m smart