A) In an experiment, a student needed to use a 0.25 M NaOH solution as standard solution. He prepared 250 mL of the working solution from a stock solution labeled as 50% NaOH. Despite knowing the concentration of the stock and working solutions, the student still needs to standardize the working solution. Give one property of NaOH that explains why the student is still required to standardize the working solution despite knowing he was preparing 0.25 M NaOH solution from the stock solution. Justify your answer. (2 marks)

How does the digestive system interact with the circulatory system? a. messages sent as electrical impulses from the digestive system are transported throughout the body by the circulatory system. b. nutrients taken in and broken down by the digestive system are carried to various parts of the body by the circulatory system. c. nutrients and gases are absorbed by organs in the circulatory system. then, they are transported to all parts of the body by organs in the digestive system. d. oxygen and carbon dioxide are exchanged by organs in the digestive system, and the gases are carried to the rest of the body by the circulatory system.