<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.
There are 4 layers.
1: Forest Floor
2: Understory
3: Canopy
4: Emergent
Given the age of the meteorite is 4.5 billion years old with 78 atoms of lead-206 the answer should be B. 156. The half-life of uranium-238 in order to decay into lead-206 is 4.46 billion years, which means that the original number of atoms is 156.
I think the answer would be d because i think thats the answer.
Insecticide or a pesticide I believe.
