How are indicator species used to assess pollution levels in the environment?

Johnny rode his bike 4 blicks down the street to his friend's house once he got to his friend house and realized he could not cone out to play he turned aroubd and went back home.what is 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 of the following is not a benefit of genetically modified foods? a.pest-resistant crops b.herbicide-resistant crops c.plants that do not require water?

The variation among individuals, on which natural selection acts