Which of these would be an appropriate null hypothesis to test related to whether meteorites hit the earth 3.6 billion years ago

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

Each hereditary trait corresponds to

Most of the carbon on earth is stored in the form of