Fossils of archaeopteryx. the carliest known bird show which of the following unique characteristics that indicate its dinosaur origins ?

How does the study of genetic disorders such as pku biologists understand normal alleles?

What's the waste product of electrons and pyruvate combining in fermentation?  

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of