Answer:
I think its A
Explanation:
Because the reason why airplane have closed windows is because we can't breathe in carbon dioxide when we go up. Of course there is oxygen just not a lot as we go up. Why would there be helium in the air? We would sound weird when we skydive.
Communicate , experiment , hypothesis, collect data
The measles virus and rubella virus are two separate viruses. They have different DNA and RNA structures, and the vaccination for the measles virus only "knows" how to attach itself to measles and destroy the virus. It doesn't know how to attach itself to the rubella virus to destroy it, as the vaccination is needed to inform it how to.
The advantage of vaccinating a large amount of the population is that it reduces the chance someone will catch sickness by a great amount, and can possibly eradicate the virus.
Answer:
Population density and transportation, Switzerland (technically), Africa
Explanation:
population density means of the population is close together and as such it can spread easier. Modern transportation I.E. buses, planes, railroads can transport large numbers of infected people to several different places within a nation and lead to more cases Switzerland is the highest per capita it has 1340 confirm cases per 1 million people however that's likely because they are able to test a large amount of the population at once whereas a larger Nations such as the u.s. or China is unable to test all their population at once and get accurate results. Africa is least affected due to not having a lot of population some together with the exception of some major cities and more industrialized countries such as Egypt and also Lacking the modern transportation systems available in more industrialized nations they don't have as many trains they don't really have too many planes able to transport infected people everywhere
