One of Galileo’s contributions to science was creating the coordinate plane system.
developing the scientific method.
improving the telescope.
inventing the astrolabe.

Developing the scientific method.

Explanation:

The scientific method is a variety of techniques for investigating certain phenomena, to collect or correct information about the Earth, life on earth or space.   There is a set of logical rules that must be adhered to during this scientific investigation, for example that the result can be measured in some way and that the experiment can be repeated.  The scientific method was created by the Italian astronomer Galileo Galilei, who devised this system as the best way to arrive at testable hypotheses about a certain scientific question.

regarding the law, the 15th amendment was specifically designed thinking in the rights of black free men.

even though ratified on february 3, 1870, the promise of the 15th amendment would not be fully applied for a long time.poll taxes and literacy tests would allow southern states disenfranchise african americans. only in 1965 the voting rights for african americans would be actually able to vote in the south.

in 1965, president johnson signed the voting rights act, which aimed to overcome legal barriers that prevented african americans from voting as it was guaranteed by the 15th amendment to the u.s. constitution.