Answer:
<h2> 3-2-1</h2>
Explanation:
PCR is the process of DNA duplication in vitro. We can make millions of copies of DNA in a very short period.
PCR completed in three steps; as in question these are
Step 1: Denaturation; Heat separation of strands of target DNA.
Step 2: Annealing; as complementary base pairing between primers and target DNA.
Step 3: Extension; Addition of DNA nucleotides by Taq DNA polymerase.
Answer: I believe it’s D. Twice
Hope this’ll help! ^^
<u>Controlling disease in commercial fisheries</u>
Explanation:
Disease outbreaks among fishes reared lead to economic loss to the fish farmers. Optimal conditions of the pond should be maintained to prevent disease spreading.
Control of disease is very challenging because fishes are cultivated in aquaponds at high density which increases direct contact among fishes making way for spread of the disease.
Natural predators will remove infected fish quickly but manual methods are time consuming and not effective.
Various steps which can be followed for prevention of diseases like good water quality, nutrition and sanitation facilities, stocking and storing of fish, recording each detail.
At the same time, disease control can easily be done by reducing the density of the stocks, application of vaccines and antibiotics and other drugs, mechanical administration of drugs, use of probiotics etc.
