What can scientists learn from the rate at which radioactive elements decay?
A. a rock's absolute age*
B. the relative age of rock layers
C. where one soil horizon ends and the next begins
D. the difference between molds and casts.
After six half-lives, what percentage of a radioactive sample will remain?
A. 0%-1%
B. 1%-3%*
C. 3%-6%
D. 6%-10%
Earth's oceans, atmosphere, and continents began to form during the first several hundred years of Precambrian time.
A. True*
B. False
A mold forms when minerals replace all or part of an organism.
A. True
B. False*
right but the last two questions are true or false so it’s
B
B
A
B
B
True
False
What scientists can learn from the rate at which radioactive elements decay is the rock's absolute age. By measuring the amount of radioactive isotopes present in a rock sample and comparing it to the known rate of decay, scientists can determine how long it has been since the rock formed or underwent a specific geological event.
To find the answer to the question about the percentage of a radioactive sample remaining after six half-lives, you need to understand the concept of half-life. The half-life is the amount of time it takes for half of a radioactive substance to decay. After each half-life, the remaining amount of the radioactive sample is halved.
To calculate the percentage remaining after six half-lives, you need to understand that each half-life reduces the amount to half, and six half-lives would halve the amount six times. So, you calculate it by taking 1/2 and halving it six times:
1/2 * 1/2 * 1/2 * 1/2 * 1/2 * 1/2
Simplifying this expression yields:
1/64
To convert this fraction to a percentage, you multiply it by 100:
1/64 * 100 = 1.56%
Therefore, after six half-lives, approximately 1.56% of the radioactive sample will remain. The correct answer is B) 1%-3%.
Regarding the statement about Earth's oceans, atmosphere, and continents forming during the first several hundred years of Precambrian time, it is False. The formation of Earth's oceans, atmosphere, and continents took much longer than several hundred years. These processes occurred over billions of years.
Lastly, the statement about a mold forming when minerals replace all or part of an organism is False. A mold is an impression or hollow space formed when the remains of an organism decay or dissolve, leaving behind a cavity. It does not involve the replacement of minerals.
The answers on this quiz from 1-7 are
B
B
A
B
B
A
B
Weird that it's repetitive Bs and As, but this is what I got and got 100%. Your welcome Connexus students!