11. memory t cells (select all that apply.) a. must all be activated in secondary lymphoid organs b. do not require co-stimulation through cd28 c. are composed only of cd4 t cells d. do not undergo somatic hypermutation e. are usually short-lived f. do not undergo isotype switching.

In which of the following relationships is one organism always benefited while the other organism is always harmed

Which ocean is on the eastern coast of north and south america? arctic ocean indian ocean pacific ocean atlantic ocean

Which of the following observation darwin shape his concept of descent with modification? a) species diversity declines farther from the equator. b) fewer species live on islands than on the nearest continents. c) birds live on islands located farther from the mainland than the bird's maximum nonstop flight distance. d) south american temperate plants are more similar to the tropical plants of south america than to the temperate plants of europe. e) earthquakes reshape life by causing mass extinctions.