Question

which of the following is the primary technique for determining the absolute age of a rock?
comparing the rock to - other geologic features
measuring the dimensions of the rock
comparing the rock to similar rocks and noting the differences
measuring radioactive decay of element isotopes

Explanation:

• Comparing the rock to other geologic features is more about relative age or geological context rather than absolute age.
• Measuring the dimensions of the rock has no direct relation to determining its absolute age.
• Comparing the rock to similar rocks and noting differences is also more about relative characteristics rather than absolute age.
• Measuring radioactive decay of element isotopes (radiometric dating) is a well - established scientific method for determining the absolute age of rocks. Radioactive isotopes decay at a known rate, and by measuring the ratio of parent to daughter isotopes in a rock sample, the age of the rock can be calculated.

Answer:

measuring radioactive decay of element isotopes