They are used in the retting of flax and hemp.

Viruses
Bacteria
Fungi
Mosses

The correct answer is: B. Bacteria.

Bacteria are used in the retting of flax and hemp. Retting is a process that separates the fibers from the woody core of the plant. This is done by soaking the plant in water, which allows the bacteria to break down the pectin that holds the fibers together. The bacteria that are used in retting are called pectinolytic bacteria. They produce enzymes that break down the pectin, which allows the fibers to be separated from the woody core.

The other options are incorrect. Viruses are not used in retting. They are too small to break down the pectin. Fungi can be used in retting, but they are not as effective as bacteria. Mosses are not used in retting. They are not able to break down the pectin.

Here is a brief explanation of each option:

  • Viruses are acellular, obligate parasites that replicate only inside living cells. They are not able to break down the pectin that holds the fibers together in flax and hemp.
  • Bacteria are single-celled organisms that are found in all environments. They are able to break down the pectin that holds the fibers together in flax and hemp.
  • Fungi are eukaryotic, heterotrophic organisms that are found in all environments. They are able to break down the pectin that holds the fibers together in flax and hemp, but they are not as effective as bacteria.
  • Mosses are non-vascular plants that are found in moist environments. They are not able to break down the pectin that holds the fibers together in flax and hemp.