What are two sources of human capital?

Investments in Education and Health are the two sources of human capital. Investments in education will lead to better qualifications, which will lead to better jobs, higher income earning potential thereby leading to improved quality of life. Investments in health will lead to a supply of healthy workforce which is an absolute necessity for higher productivity and economic development. You can read about the Human Capital Index – Key Areas of Measurement, Objectives and Significance in the given link.

Further readings:

1. Topic-Wise GS 3 Questions for UPSC Mains
2. Human Development Report – HDR 2020, 5 Indices, Gender Development Index