What information does "9" give about an atom of fluorine? Select three options

The number of living organisms in a particular area is

Which best describes how the common cold spreads in the human body? a bacteria burst out of normal cells killing them b viruses replicate inside respiratory cells c bacteria inject dna into normal cells d viruses insert dna into bacteria

Each member of a class sampled a piece of ptc testing paper. thirty people sampled the chemical. twenty persons were tasters. how many had heterozygous genes? 10 20 0-20 indeterminate