Which biome contains permafrost? tropical rain forest temperate rain forest savanna tundra

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 of the following describes a difference when gram-positive bacteria are compared to gram-negative bacteria?

What in scientific term why the salty popcorn causes this thirst