<span>In the sentence "The first animal cloned by nuclear transfer was a _____ named Dolly", the word that correctly completes the sentence is sheep. A sheep named Dolly is the first animal cloned from an adult somatic cell by nuclear transfer. She was cloned at the Roslin Institute of the University of Edinburgh, Scotland, in 1996. There she died in 2003.</span>
Explanation:
Molecular formulas show correct and accurate number of each type of the atoms which are present in molecule.
On the other hand, structural formulas show arrangement of atoms and covalent bonds between them.
For example,
The molecular formula for carbon dioxide is 
The structural formula is O = C = O