Looking at the structure of caffeine below, which position acts as a lewis base?.

Assessment includes a. interviews, recorded conversations, videos, frequency counts, and time samples. b. formal standardized tests and developmental screening tools. c. various types of documented observations, documentation of child work, checklists, rating scales, and standardized tests. d. anecdotal notes, narratives or daily records, daily health checks, and teacher observation checklists.

Which of these international trade concepts results in specialization and trade increases in total world output? a) absolute advantage b) balance of payments c) absolute advantage d) international tariffs

How do you work out 21.3-8= show your working. plz