In 2006,scientists Discovered a Fossil That Had Scales and Gills,a

question 21

Multiple Choice

In 2006,scientists discovered a fossil that had scales and gills,a flat head with eyes on top like a crocodile,and fin and neck bones that would allow it to prop itself out of the water.The best explanation for this fossil is that it is

• A)a transitional fossil between fish and amphibians.
• B)a transitional fossil between amphibians and reptiles.
• C)a ray-finned fish.
• D)a modern amphibian.

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Definitions:

Distillation

A process used to separate mixtures based on differences in their volatilities in a boiling liquid mixture.

Stereochemical Configuration

The spatial arrangement of atoms in a molecule, determining its geometric structure and influencing its chemical properties and reactivity.

D-Threonine

One enantiomer of the amino acid threonine, characterized by its specific spatial arrangement of atoms, which is important in biochemistry and molecular biology.

Enantiomer

Molecules that are mirror images of each other but cannot be superimposed onto each other, usually involving chiral centers.