Oral polio vaccine is highly effective and inexpensive (about US$0.10 per dose, or US$0.30 per child and its availability has bolstered efforts to eradicate polio. A study carried out in an isolated Eskimo village showed that antibodies produced from subclinical wild virus infection persisted for at least 40 years. Because the immune response to oral polio vaccine is very similar to natural polio infection, it is expected that oral polio vaccination provides similar lifelong immunity to the virus.
Contact immunity to polio can occur when attenuated poliovirus derived from the oral polio vaccine is excreted, and infects and indirectly vaccinates unvaccinated individuals.
a cell is the smallest structural and functional unit of an organism
The genetics of red hair appear to be associated with the melanocortin-1 receptor (MC1R), which is found on chromosome 16. Eighty percent of redheads have an MC1R gene variant.
I cannot find this source for this I'm sorry. I meant to add it but I lost the site
I am not sure but I believe it is B. Precipitation because the definition is: <span>the action or process of precipitating a substance from a solution ^-^ Hope this helps</span>