Two kinds of organisms that cannot reproduce with each other are separate

The observations of hooke and van leeuwenhoek documenting the existence of microscopic cells formed the basis of what important theory? a. the cell theory stating that all living things are composed of cellsb. the theory of spontaneous generation, which held that life forms could arise spontaneouslyc. the theory of chemotherapy, or use of antimicrobials to destroy pathogenic organismsd. the germ theory of disease and causative agents

The sketch shows a rynchosaur, an extinct animal that is known only from fossils. there has been much debate about the classification of these creatures. some scientists suggest that they belong with primitive amphibians, and some think they are related to snakes and lizards.the data equally support both cases. which statement best explains how to draw a cladogram that includes the rynchosaur? draw the cladogram for amphibians. draw the cladogram for reptiles. draw two cladograms, both showing the traits, and leave it as a hypothesis. draw two cladograms, both showing the traits, and have scientists vote

Genetic disorders can result when sister chromatids fail to seperate properly. during what phase is this problem most likely to occur?