The Speed of H I Gas Clouds Can Be Found

question 1

Multiple Choice

The speed of H I gas clouds can be found using the

• A) Doppler effect of radio signals.
• B) 21-cm spin-flip transition.
• C) temperature of the clouds.
• D) mass of the clouds.

---

Definitions:

Molecular Clock

The molecular clock is a method used to estimate the time of evolutionary divergence between species by comparing genetic differences and assuming a constant rate of molecular change.

Mutations

Mutations are changes in the DNA sequence of an organism's genome, which can result in new phenotypes and contribute to genetic variation.

Lineages

Sequences of species descending from a common ancestor, often shown in phylogenetic trees to illustrate evolutionary relationships.

Ancient Cetacean

Refers to the early, now-extinct members of the order Cetacea, which includes whales, dolphins, and porpoises.