When a scientist contrasts two or more objects what is he or she looking for? a. differences b. causes and effects c. changes d. errors which is it?

Which of the following substances is not involved in the chemical reaction that pro- duces smog? a. sunlight b. particulate matter c. automotive exhaust d. ozone

Which of the following is the best definition of aerobic respiration? o a. the cellular process that releases energy by breaking down glucose o b. physical activity that involves the repeated motion of large muscle groups o c. physical activity that increases heart rate and breathing rate o d. the cellular process that converts solar energy to chemical energy

Which of the following was not a major animal on land during the carboniferous period? amphibians insects both a and b none of the above