Which would be the best tools to measure the density of a small piece of silver ore

What is the name of the two satelites on mars

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

Connection compare and contrast genetic engineering to the process of natural selection. select all statements that are true.