What are carefully defined units of analysis that can be manipulated statistically and can yield correlations?

Which of the following represents a negatively charged ion? of t 7

Sperm pass through the and connect to a short ejaculatory duct. vas deferens prostrates seminiferous tubules none of the above

Which of the following is the best definition for the process of photosynthesis? a.) plants digest sugars to make energy. b.) plants use oxygen and glucose to make carbon dioxide. c.) plants use sunlight and carbon dioxide to make sugars. d.) plants use sunlight to make chlorophyll and chloroplasts.