How Do Scientists Calibrate a Molecular Clock for a Group

question 63

Multiple Choice

How do scientists calibrate a molecular clock for a group of organisms with known nucleotide sequences?

• A) They use radioactive isotopes to measure the age of DNA material directly.
• B) They graph the number of nucleotide differences against the dates of evolutionary branch points known from the fossil record.
• C) They analyze fossilized DNA of known age and compare its nucleotide sequences to modern DNA sequences.

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Definitions:

Torana

Gateway in the stone fence around a stupa, located at the cardinal points of the compass.

Stupa Mound

A dome-shaped structure originally built to house Buddhist relics and serve as a place of meditation.

Triratna

A tripartite symbol of the three jewels of Buddhism—the Buddha himself, his dharma, and the sangha.

Mahadeva

refers to a principal deity, Shiva, in Hinduism, representing aspects such as creation, protection, and destruction.