Small fragments of infectious that cause disease in tissue are called . an example of a disease that is caused by this is . this disease can be spread from to humans by consuming infected meat. these infectious agents are neither cells nor , and research into how they cause disease is ongoing.

The correct answer will be-

1. Proteins

2. Nervous

3. transmissible spongiform encephalopathies.

4. Mad cow disease

5. Cow

6. Virus

Explanation:

Prions are the infectious particle composed of harmless proteins found in the brain of the animals like humans, cows which are responsible for the degeneration of the nervous tissues of the brain.

These proteins of the prions are resistant to the enzymatic actions and thus they can multiply and accumulate within the neurons and destroys them forming holes in the neurons giving the sponge-like appearance and thus disease is known as transmissible spongiform encephalopathies.

An example of this disease is mad cow disease which spreads from the cow to human by eating the meat of the cow especially brain contaminated with prions which are neither considered viruses nor cells.