3 - Exposure to radiation
Radiation ionises cells and can cause mutations in genes.
The rest of the options have no affect on genetics at all, merely a temporary affect on the physical aspects of the body, such as heart rate etc.
"resting membrane potential"
Resting potential occurs when membrane potential isn't altered by action potentials. When a membrane is polarised and there's no sinaptic potentials or any other active change of the membrane potential we are before a resting membrane potential.
<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.
The flattening of our solar system likely helped changed random motions into more orderly ones
