What led to the conclusion that single-celled prokaryotic organisms evolved in the absence of oxygen

What volume of a 0.25 m solution can be made using 0.55 moles of ca(oh)2

Body systems are not completely independent they integrate and work together describe one example of the integration between body systems

What function does a limb serve in each animal how are the limb bones of the four animal similar based on the similarities what can be inferred about the evolution of the poor animals