While Taking a Hike in the Forest, You Find Some

question 29

Multiple Choice

While taking a hike in the forest, you find some fossils in layers of sedimentary rocks whose age, you later find out, is said to cover a span of 100-400 million years. You decide to send the fossils out for analysis to a company that dates rocks by radioactive decay, and, some weeks later, receive a report informing you that a volcanic ash bed associated with one of the fossils has a 1:1 ratio of ²³⁵U: ²⁰⁷Pb. Do these data support or refute the assumed age of the rocks in which the fossil was found? (Note: The half-life of ²³⁵U is about 704 million years.)

• A)Yes, because the rock layers are less than 704 million years old.
• B)Yes, because the ratio of ²³⁵U to ²⁰⁷Pb represents one half-life and that would be approximately 350 million years old.
• C)No, because the ratio of ²³⁵U to ²⁰⁷Pb represents one half-life and that would be about 700 million years old.
• D)No, because the rock layers are less than 704 million years old.

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Definitions:

Local Heat Application

A therapeutic method used to relieve pain or accelerate healing wherein heat is applied to a specific area of the body.

Vasodilatation

The widening of blood vessels, which decreases blood pressure and increases blood flow to certain areas of the body.

Piloerection

The involuntary erection or standing up of hairs on the skin due to cold, fear, or emotional stimuli, commonly known as goosebumps.

Perspiration

Perspiration, also known as sweating, is the release of a salty fluid from the body's sweat glands as part of the process of regulating body temperature.