I have been working on these questions the whole but cannot seem to figure them out.

Please provide answers and explanations.

Thankyou so much for your help

25. Capillary endothelial cells of the blood brain barrier: A. are connected by tight junctions B. contain P-glycoprotein, which helps drug molecules to cross into brain tissue C. contain phospholipids that help to repel some drugs D. prevent as much as 98% of potentially beneficial drugs from reaching the brain 26. Excipients in a tablet could include: A. a buffering agent B. a colouring agent C. a lubricant D. an active drug 27. The core battery of pharmacology studies that are required to demonstrate the safety of a drug for use in man include studies on the: A. cardiovascular system B. central nervous system C. genito-urinary system D. respiratory system 28. Methods for studying the metabolism of drugs make use of: A. computer algorithms to predict the stability of molecular structures B. hepatocytes isolated from liver C. microsomes prepared from liver hepatocytes D. S9 cell fractions containing the cytosol and nucleus 29. Phase II metabolic reactions generally result in drug molecules: A. becoming more water soluble B. being less pharmacologically active C. being more easily excreted D. having a smaller molecular weight 30. Pharmacodynamic biomarkers indicate: A. how a drug is metabolised B. if a drug has interacted with a target C. if a drug has modulated a target D. the efficacy of a drug candidate20. The ECso of drug B is: A. 10*M B. 10"M C. 10* M D. 10'M 21. What is the order of drug potency (lowest to highest)? A. A