Human capital refers to the knowledge, skills, and health embodied in individuals that enables them to perform labor and produce economic value. An educated and healthy person is considered human capital because they are productive, while an uneducated or unhealthy person is not. India's software companies employ many physically challenged people because, though physically limited, they are educated and trained, making them productive human capital. Physical capital consists of machinery, buildings, and other tangible assets used in production. Both human capital and physical capital are investments that depreciate over time but contribute to economic growth, though human capital cannot be separated from its owner like physical capital can.