Vertebrates share many physical characteristics. all vertebrates a. have an internal skeleton that includes a backbone or spinal column. b. have a thick exoskeleton but not an internal skeleton c. have neither an exoskeleton nor an internal skeleton. d. have an internal skeleton but not a backbone or spinal column.

There are six elements that make up most of the human body. which of the following is not one of these six elements?

Humans are believed to have evolved in coastal regions in east africa. the region had an abundant supply of fish for early humanoids to eat. when scientists analyze the fads gene they see an interesting pattern. people whose families have lived in this area of east africa for generation show a high level of diversity in alleles for the fads gene. conversely, people whose families had migrated inland a moderate distance from sources of fish showed a much lower diversity for fads gene alleles. additionally, the fads alleles found in people whose family has lived inland for generation are almost all gene alleles which produce fads proteins with a high level of function and activity. how do anthropologists explain this?

Food webs - transferring energy and matter from one level to another. here you see four food webs. one or more are incorrect. which food web(s) show the correct sequence of organisms, from start to top level consumer? a) a b) d c) c d) a and d