How does Docker improve application deployment and scalability?

Docker improves application deployment and scalability by packaging applications and their dependencies into containers, ensuring consistency across environments. Lightweight and quick to boot, containers make application deployment and updating easier with zero downtime. Docker enables horizontal scaling since it can run multiple containers parallel to each other, thus distributing the work efficiently. It is easy to scale Docker up or down in response to demand with the help of orchestration tools, including Kubernetes. The guarantee of portability means consistency in running applications from development through testing to production, thus reducing errors in deployment. By applying isolation at the container level, Docker increases resource utilization and simplifies scaling of modern dynamic workloads.