Communicable disease was once the major challenge of public health; current priorities are based on

Spherocytosis is an inherited blood disease in which the erythrocytes (red blood cells) are spherical instead of biconcave. this condition is inherited in a dominant fashion, with sph- dominant to sph+. in people with spherocytosis, the spleen "reads" the spherical red blood cells as defective, and it removes them from the bloodstream, leading to anemia. the spleen in different people removes the spherical erythrocytes with different efficiencies. some people with spherical erythrocytes suffer severe anemia and some mild anemia, yet others have spleens that function so poorly there are no symptoms of anemia at all. when 2400 people with the genotype sph- sph+ were examined, it was found that 2250 had anemia of varying severity, but 150 had no symptoms. does this description of people with spherocytosis represent incomplete penetrance, variable expressivity, or both? explain your answer. (3 points)

Example of health promoting behavior

Which of the following best reflects what we know about how the flu virus moves between species? a) the flu virus in a pig is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected.b) a flu virus from a human epidemic or pandemic infects birds; the birds replicate the virus differently and then pass it back to humans.c) an influenza virus gains new sequences of dna from another virus, such as a herpesvirus; this enables it to be transmitted to a human host.d) an animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates, the virus is passed to a new species such as a bird, and the virus mutates again and can now be transmitted to humans.