Step-by-step explanation:
heliocentric means having the sun in the middle/center in the solar system
geocentric means having the earth in the middle/center in the solar system
therefore your answers are:
the planets orbit the sun.
in 1543, Nicolaus Copernicus proposed the theory.
the evidence that led people to believe this was when Galileo observed that four moons orbited around Jupiter. in other words, heliocentric.
most of the stars are located in the milky way galaxy.