The discovery of a pigeon-sized dinosaur with bat-like wings has exposed bizarre twists in the early evolution of birds, said scientists in China Wednesday whose conclusions were immediately challenged.
Although closely related to the notorious carnivore Tyrannosaurus rex, a new lineage of dinosaur discovered in Chile is proving to be an evolutionary jigsaw puzzle, as it preferred to graze upon plants.
Many years of research have shown that for students from lower-income families, standardized test scores and other measures of academic success tend to lag behind those of wealthier students.
Look at a primate or a Neanderthal skull and compare it with a modern human's. Notice anything missing?