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Researchers have long debated different hypotheses for the p…

Researchers have long debated different hypotheses for the phylogeny and classification of species in the bear family, Ursidae. In 2008, researchers obtained complete mitochondrial DNA (mtDNA) genome sequences for the eight living species of bears. Based on these data, the researchers constructed a phylogenetic tree for the family Ursidae. Based on the phylogeny, who is the closest relative of the American black bear?

In some species of oysters found in shallow, rocky waters, b…

In some species of oysters found in shallow, rocky waters, both light and dark-colored shells are common, whereas intermediate-colored oysters are rare. This is likely because lighter oysters are similar in color to the rocks, while dark oysters blend into the shadows cast by the rocks. Intermediate-colored oysters are heavily preyed upon by crabs and other predators due to being more conspicuous. Selection for these two extreme phenotypes is an example of  

The below image represents an atom of a specific hypothetica…

The below image represents an atom of a specific hypothetical element and its own cation.   Which image represents the cation?  Y represents the cation  X represents the cation  What supports your choice?   Cations are larger than their neutral atom Cations are smaller than their neutral atom  Why does this occur?   Because cations lose electrons from the outer most shell, the remaining electrons have a stronger attraction to the nucleus and are pulled closer, thereby making the ion small Because cations gain electrons, the incoming electrons will be repelled by the existing electron and therefore the shell will expand to accommodate them.