Four different blood types are found in human populations because of and .

What feature of cell theory is best demonstrated in the image

After getting the slide and microscope ready, stella is eager to see the microscopic pond water specimen! she crouches around her microscope and aligns her eye with the microscope’s eyepiece. but she's only able to see a bright white light. at this point, no specimens or cells are visible on stella's pond water slide. after taking a moment to collect her thoughts, stella realizes she can't see any lifeforms because .

Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment