Three main categories of freshwater ecosystems are

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

Which type of bond forms between water moleculesstrong bondhydrogen bondcovalent bondpolar bond

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