Natural selection acts on

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

Hershey and chase confirmed that dna, not protein, was the genetic material. how do the results of their two experiments support this conclusion?

Astudent measured the amount of carbon dioxide (co2) produced by yeast during an experiment. use the data in the table at the right to answer the questions below. which variable is the dependent variable?