What does the term biodegradable often refer to

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

Explain how scientists use geologic time to determine the age of landforms.

What factors contribute to the effect an environmental toxin has on the human body?