Answer:
(1) Nitrite poisoning
(2) Its cause is elevated levels of nitrite in the pond or culture system water.
Answer:
Plasmids are used in biotechnology.
Explanation:
A plasmid is a natural or artificially modified circular DNA molecule for use in biological research.
The researchers use the plasmids to insert a DNA fragment of interest, thanks to the cloning cassettes. They can clone genes to express proteins or RNAs and analyze them.