What do biologists use to establish whether or not two organisms are the same species

Plz plz plz quick! 49 points for whoever which of the following statements about greenhouse effect is true? *life on earth is suffering because of greenhouse effect *the greenhouse effect is caused by human activity *all greenhouse gases are harmful *life on earth would not exist without the greenhouse effect

Cultures of the lake of the ozarks water samples were grown on enrichment media for identification. however, these organisms are present to some degree in all samples. an important question from a clinical perspective is whether or not there is a significant increase in the fecal coliform populations that would put people's health at risk. if you were part of the team investigating this outbreak, how would you best enumerate the fecal coliform threat? view available hint(s) cultures of the lake of the ozarks water samples were grown on enrichment media for identification. however, these organisms are present to some degree in all samples. an important question from a clinical perspective is whether or not there is a significant increase in the fecal coliform populations that would put people's health at risk. if you were part of the team investigating this outbreak, how would you best enumerate the fecal coliform threat? direct microscopic counts filtration count culture serial dilution count culture plate count culture

What does polymerase chain reaction (pcr) do? o a. separates dna fragments by size o b. cuts a dna sample into fragments o c. provides an overall picture of a person's chromosomes o d. makes more copies of a sample of dna