All galaxies are held together by gravity, but based on what we can see (stars, nebulae, etc.) , there shouldn’t be enough gravity to do the job. That is why scientists believe that all galaxies are partially held together by a substance called , which we can’t see.

Which of the following is an example of negative reinforcement? a. marty knocks over his mother's prize fern so she gives him a time out. b. gwen mows the lawn and her dad takes her out for ice cream. c. tara takes an aspirin, and her headache begins to go away. d. peter comes in late from his lunch and is fired from his job.

What is the function of the organelle labeled a in the diagram?

Ill give you free brainliest + free points if you answer this drvers ed question correctly! when merging, yield to traffic a. already on the road you're joining b. on your right side only c. if it's going slower than you d. if it's going the same speed as you