An international standard used as a carbon isotope standard is
A) Troilite.
B) V- SMOW.
C) atmospheric air.
D) PeeDee belmnite.

Question

Quizplus · Accepted Answer

PeeDee Belemnite (PDB) is a fossil belemnite that has a well-defined and stable carbon isotope composition, and is commonly used as a reference standard in isotope geochemistry. Troilite is also used as a sulfur isotope standard, V-SMOW is a standard for oxygen and hydrogen isotopes in water, and atmospheric air is used as a reference for noble gas isotopes. However, PDB is the most widely used carbon isotope standard.

An International Standard Used as a Carbon Isotope Standard Is