A scientist is observing a eukarotic cell and a prokaryotic cell. Which structure could she only observe in the eukaryotic cell?

A well defined nucleus and cell organelles.

Explanation:

Eukaryotic organisms are those organisms which have true nucleus or membrane around the nucleus in its cell. In eukaryotic cells organelles such as mitochondria, ribosome, lysosomes, endoplasmic reticulum, golgi bodies and vacuoles are present. In prokaryotic cell, all the activities are performed by a single cell while in eukaryotic cell, organelles are present which performs specific functions.

amber has allowed scientists to study dna that has been preserved over millions of years.