When b-lymphocytes are exposed to an appropriate antigen, they proliferate into plasma cells and ?

The images show fossils of a modern bird and two extinct organisms (a tyrannosaurus rex and an archaeopteryx). based on the structure of the three organisms, it can be concluded that . the archaeopteryx and bird have wings, while dinosaurs have limbs. so, it can be concluded that .

Competition occurs between species when

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?