45. spectroscopy is a) the study of sunlight b) the study of the properties of light c) the study of distant stars d) the study of vision

Spectroscopy is B) the study of the properties of light

Explanation:

Spectroscopy in the study of properties of light began with the study of visible light and how it can be dispersed by a prism because of light's wavelength.

answer; (b); i believe its indefinite existence of human population in a healthy and prosperous condition;