In 1687, explained that gravitational forces hold the solar system together.

a. newton

b. corpenicus

c. halley

d. galileo

The answer for #3 is c but i don't know why

How heavy is thanos? a) 3000 lbs b) all of it c) the price of tea in china d) heavy enough

Ageochemist examines a piece of metal that he found in the soil. he performs tests to identify the metal from its density, electrical conductivity, and melting point. which statement best describes his investigation? a. he is determining physical properties that are sufficient to identify the metal. b. he is determining chemical properties that are sufficient to identify the metal. c. he is determining physical properties that are insufficient to identify the metal. d. he is determining chemical properties that are insufficient to identify the metal.