Can you help me with with these questions?

Johnny rode his bike to a friend's house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was not able to play. what was his displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point

Which group of protists would be most likely to have cilia as adults and why? (1 point)the sporozoan protists would since they have to spread their spores around.the heterotrophic protists would since they use them to gather food.the parasitic protists would since they need to find other organisms to attack.the autotrophic protists would since they must move to find light.

The backbone of the double helix has an alternating molecules. what do you call these alternating molecule?