Explanation: Birds represents an example of natural reservoir host for the three zoonotic pathogens. For example poultry for salmonellosis and influenza from which house cats, humans and birds of prey can be infected. In the case of Toxoplasma gondii pigeons represent a better example of reservoir host.
Scientists usually use the potassium-argon method to date rocks that are older than about 1 million years. Uranium-238 is also used for radiometric dating. It has a half-life of 4.5 billion years. It decays to produce lead-206.
The first thing a cell needs to do to divide successfully is to "B.increase its ratio of surface area to volume". This allows the cell to reach a "breaking point" at which it can divide into two separate cells.
