You didnt exactly put in any answer options...
But here is my answer: Comparing a desert to Mars, i would say that
A desert has oxygen
And mars has carbon dioxide
A desert has sand
Mars has a rocky surface
Mars is a planet
A desert is not
The things i could think of that a desert and planet mars can relate to...I would say they both have heat and both sometimes have dust storms.
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.
They all contribute to genetic diversity, alternative D.
Answer:
Its C I had the same question and got it right