Which of the following situations describes someone who is experiencing eustress?

david is very excited about his first soccer match this friday. he feels confident because he has practiced well all week.
jenny feels very scared and nervous for a speech she has to give in her history class. she is not sure she will remember what she needs to say.
maggie often feels anxious since she began arguing with her best friend recently. she just does not want to fight with her friend anymore.
matt feels confused about his home life because his mom left suddenly a couple weeks ago. he gets sick often and is not eating well.

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)

Aresearcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (tmv). the cell contents are left in a covered test tube overnight. the next day this mixture is sprayed on tobacco plants. we expect that the plants would ) develop some but not all of the symptoms of the tmv infectionb) develop the typical symptoms of tmv infectionc) not show any disease symptomsd) become infected, but the sap from these plants would be unable to infect other plants

In 2009, a flu pandemic was believed to have originated when viral transmission occurred from pig to human, thereby earning the designation, "swine flu." although pigs are thought to have been the breeding ground for the 2009 virus, sequences from bird, pig, and human viruses were all found within this newly identified virus. what is the most likely explanation of why this virus contained sequences from bird, pig, and human viruses? a) the virus was descended from a common ancestor of bird, pig, and human flu viruses.b) the infected individuals happened to be infected with all three virus types.c) related viruses can undergo genetic recombination if the rna genomes mix and match during viral assembly.d) the human was likely infected with various bacterial strains that contained all three rna viruses.