Please anyone help me

Which characteristics can be used to differentiate star systems? check all that apply.

The famous scientist galileo galilei did several experiments with sloping planes, which he rolled metal balls down so that he could study motion. by changing the slope, he could study how the speed at which the ball rolled was affected. what was the independent variable in galileo's experiment? a. the speed of the ball b. the slope of the plane c. whether the ball moved d. what the ball was made of

How many moles of cu are needed to react with 5.8 moles of agno3? cu + 2 agno3 → cu(no3)2 + 2 ag