A Radiometric Age for a Mineral Crystal Within an Igneous

question 2

Multiple Choice

A radiometric age for a mineral crystal within an igneous rock measures the amount of time that has passed since the

• A) atoms within the crystal were part of a body of molten magma.
• B) crystal solidified.
• C) temperature of the crystal became equal to surface temperatures.
• D) temperature of the crystal became equal to the closure temperature for the mineral.

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Definitions:

Human Activities

Actions and endeavors undertaken by humans that impact the environment, including industry, agriculture, and recreation.

Environmental Factors

External elements that influence living organisms, including climate, terrain, water, nutrients, predators, and competitors.

Spicules

Slender skeletal spikes made of calcium carbonate or silica; found in sponges and some other animals.

Amoeboid Cells

Cells that move or feed by forming extensions of their cytoplasm called pseudopodia, typical of amoebas.