What major body system(s) is the earthworm lacking? how might this affect the earthworms way of life?

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 .

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important

What is used to keep track of the gamates and possible offsprings combination