(this is a question from my leap practice) how did scientists discover dark matter? a. they discovered that something was holding the universe together. b. they detected the presence of matter that they could not visibly see. c. they discovered visible matter holding galaxy clusters together. d. they realized that something had to ignite the original explosion that caused the big bang.

10 points! will mark brainiest! in a heat engine if 1,000 j of heat enters the system and the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2,000 j 1: write the equation 2: list out your known variables 3: plug the numbers into the equations 4: solve 5: write your solution statement that includes initial energy and final energy added you so much!

Gravity is pulling an object into the sun. the closer the object gets to the sun, the greater the gravitational force that acts on the object, increasing its acceleration. a line graph plotting the speed of the object against time would have which shape? a: straight line of positive slope b: curved line that slopes upward c: curved line that slopes downward d: straight line of negative slope

During which step of the scientific method does a scientist make an educated guess about the outcome of an experiment? a. form a hypothesis b. analyze the results c. design an experiment d. collect data