Title: Stars and gas in the most metal-poor galaxies
Abstract: Future large telescopes like JWST and the ELTs will obtain rest-frame UV spectroscopy of thousands of galaxies in the redshift range between 10 and 15. These observations will challenge our understanding of stars and gas at extreme-low metallicity. In this talk, I discuss how we are using the nearest most metal-poor galaxies known to test model galaxy spectra of the kind that will be used to interpret observations of primeval galaxies. I include results from our pilot and extended HST COS programs. Studies like ours are critical to better understand how extreme-low metallicity affects the properties of stars and gas, and ultimately the nature of the main sources responsible for Cosmic Reionization.