Here's why:

* Viruses are not capable of independent reproduction. They lack the necessary cellular machinery and enzymes to replicate on their own. Instead, they rely on hijacking the host cell's machinery to make copies of themselves.

Let's look at the other statements:

* Nucleic acid core: This is accurate. Viruses contain either DNA or RNA as their genetic material.

* Capsid: Also accurate. The capsid is a protein shell that encloses and protects the viral genome.

* Seek out specific host: This is accurate as well. Viruses have specific proteins on their surface that bind to receptors on the host cell, determining which cells they can infect.

In summary: Viruses are obligate intracellular parasites, meaning they cannot reproduce without a host cell.