_____ is useful for dating very old rocks because it has a half-life of 1.3 billion years.
A. thorium-232
B. potassium-40
C. uranium-235
D. carbon-14
is the answer D?
http://www.google.com/#q=half-life%2Bof%2B1.3%2Bbillion%2Byears
http://www.google.com/#q=carbon+14+half+life
potassium-40
No, the correct answer is C. Uranium-235.
To determine the correct answer, we need to understand the concept of half-life and its application in dating rocks. Half-life is the time it takes for half of the radioactive parent atoms in a sample to decay into stable daughter atoms.
Carbon-14 (D) is commonly used for dating organic material up to around 50,000 years old, but it is not useful for dating very old rocks. Carbon-14 has a relatively short half-life of about 5,730 years.
Thorium-232 (A) has a half-life of about 14 billion years, making it useful for dating extremely old rocks, but not specifically for rocks with a half-life of 1.3 billion years.
Potassium-40 (B) does have a half-life of 1.3 billion years and can be used for dating rocks of this age range. However, it is not the best option for dating very old rocks because it can be affected by other factors that can complicate the dating process.
Uranium-235 (C) is the most suitable answer. It has a half-life of 1.3 billion years, making it highly useful for dating very old rocks. Additionally, uranium-235 is commonly found in rocks, which further enhances its utility for dating purposes.