### Q1: What is the primary function of APIs in connecting front-end and back-end systems?  
### Q2: How can you optimize API calls to improve front-end and back-end communication?  
### Q3: What are some advanced techniques for enhancing real-time data communication between front-end and back-end systems?  
### Q4: In what ways can seamless front-end and back-end integration benefit a business's customer satisfaction?  
### Q5: What potential issues could arise from inefficient communication between front-end and back-end systems during peak usage times?  
### Q6: Describe a scenario where improved front-end and back-end integration could enhance user engagement in an online shopping application.  
### Q7: How can clear error messages improve communication between front-end and back-end systems?  
### Q8: Why is it important to ensure that the back-end is capable of handling expected loads during user interactions?  
### Q9: How can effective communication strategies between front-end and back-end systems lead to better application performance metrics?