Viruses did not find a place in Whittaker's five kingdom classification due to their non-cellular structure.

Explanation:
Whittaker's five kingdom classification system was proposed in 1969 by American scientist Robert Whittaker. This system classified organisms into five kingdoms based on their characteristics and evolutionary relationships. The five kingdoms are Monera, Protista, Fungi, Plantae, and Animalia.

- Monera: This kingdom included prokaryotic organisms, such as bacteria, which are single-celled and lack a nucleus.
- Protista: This kingdom included eukaryotic organisms that are mostly unicellular, such as protozoa and algae.
- Fungi: This kingdom included eukaryotic organisms that are heterotrophic and absorb nutrients from organic matter in their environment. Fungi are multicellular, except for yeasts.
- Plantae: This kingdom included eukaryotic organisms that are multicellular, autotrophic, and have cell walls made of cellulose. It includes plants.
- Animalia: This kingdom included eukaryotic organisms that are multicellular, heterotrophic, and lack cell walls. It includes animals.

Viruses, on the other hand, are acellular entities that are not classified within any of the five kingdoms. They are considered to be on the border of living and non-living due to their unique characteristics. Viruses lack cellular structure and cannot carry out metabolic processes independently. They require a host cell to replicate and are considered obligate intracellular parasites.

Viruses consist of genetic material (DNA or RNA) enclosed in a protein coat called a capsid. Some viruses may also have an outer envelope. They cannot carry out essential life processes such as respiration, growth, or reproduction outside a host cell.

Due to their acellular nature and lack of independent metabolism, viruses do not fit into the traditional classification system based on cellular organization. They are often studied separately in the field of virology.

In summary, viruses did not find a place in Whittaker's five kingdom classification because of their non-cellular structure and unique characteristics as obligate intracellular parasites.