What’s 2+2? I need the answer

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

Do you want free brainliest and free points? answer this drivers ed question correctly and ill give you both : ) how can you count following distance? a. look for a moving object and count the seconds it takes for you to pass it after the car you are following has passed it. b. look for a stationary object and count the seconds it takes for you to pass it after the car you are following has passed it. c. look for the rear wheels of the car in front and count the number of rotations. d. look for the stripes on the road and count them as you pass by.

This is an ap world history question. i am working on a worksheet which has a vent diagram with each circle labeled either us or byzantine economy. the middle is the similarities. can someone explain to me the similarities and especially the differences between the two?