Watson and Crick discovered the two strands in DNA run in perpendicular directions.
run in the same direction
run in opposite directions
run in random directions

Which statement about relative potential energy of electrons is correct? a. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 2 s orbital of the second electron shell. b. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 3 p orbital of the third electron shell. c. an electron in the 3 p orbital of the third electron shell has more potential energy than an electron in the 2 p orbital of the second electron shell.

Which of the following types of pollution is most responsible for large numbers of deaths worldwide because of unsafe drinking water? (a) nutrient pollution (b) thermal pollution (c) pathogen pollution (d) sediment pollution

What is any method of measuring the age of an object or event in years, such as using atomic half-life?