Acquired immunodeficiency disorder is the result of pathogens that target witch cell?
- memory b-cells
- cytotoxic t-cells
- t-cells
- natural killer cells

19. scientists use meteorites that hit earth to provide evidence of the composition of earth's interior because they hypothesize that

Ascientist separates a population of mice into two groups. what would most likely increase the rate of speciation in this population. a. teach the two groups different tricks b. allow the two groups to breed with each other c. put the two groups in different environment d. have the two groups live in identical ecosystems

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