They replace the lost ions by active uptake through active transport
of ions from the surrounding waters. This is exhibited in freshwater fishes that
actively take in these ions through the gills. Most of the ions involved in osmoregulation in freshwater are those of Na+ and Cl-.
I would say the scientific method?
Answer:
The influenza H1N1 virus is transmitted through saliva droplets and mucus from sick people, who by sneezing or coughing without covering their mouth and nose adequately, leave the virus in the air or on their hands, infecting then the objects they touch. As a rare occurrence, a person can become infected with the flu by touching a surface or object contaminated with the influenza virus and then touching the mouth, nose, or eyes.
Pigs sometimes transmit influenza H1N1 virus to people, primarily pig farmers and veterinarians.