How does variation impact natural selection?

Which would not reduce the amount of green house gasses in the air

Which of the following are used in an electrochemical cell? a. electrodes b. electrolyte c. terminals d. all of the above

Greg drew a diagram to compare two of the fundamental forces. which labels belong in the areas marked x, y and z? gravitational force electromagnetic force x. attractive y repulsive z: infinite range x: infinite range y attractive z. repulsive x. always attractive y: infinite range z: attractive or repulsive x. attractive or repulsive y infinite range z: always attractive