Step 1: Identify common host organisms for cloning.
- Prokaryotic hosts: *E. coli* is a prevalent prokaryotic choice.
- Eukaryotic hosts: Yeast, specifically Saccharomyces cerevisiae, is frequently employed as a eukaryotic host.
Step 2: Evaluate the provided options.
- *E. coli*: Prokaryote; unsuitable for this context.
- Yeast: Eukaryote; a well-established cloning host. Applicable.
- *Xenopus*: Utilized in developmental biology; not a standard cloning host.
- Nurosopra (likely *Neurospora*): A model fungus; not a primary cloning host.
Step 3: Determine the correct answer.
Therefore, Yeast is the standard eukaryotic host for cloning.