Describe the two types of energy changes that can occur in a chemical reaction.

Explain how organisms could be harmed by high levels of salt from roadways?

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled

Suppose you are provided with an actively dividing culture of e. coli bacteria to which radioactive thymine has been added. what would happen if a cell replicates once in the presence of this radioactive base?