Why does a person have to get a flu shot every year? Why isn't one flu shot for life enough?

Which type of neuroglia is found outside of the brain?

It is believed that europa, one of jupiter’s moons has an ocean beneath its surface. based on how earth’s oceans and atmosphere are believed to have formed, what can be said about europa’s supposed ocean? the arrival of in the early days of europa’s existence could have formed its ocean. it is likely that the water experienced , similar to earth. it is also possible that this water is retained beneath europa’s surface and in its atmosphere due to europa’s .

Which of the organisms listed below performs nitrogen fixation? a. legumes b. plants c. bacteria d. fungi