Which laboratory activities involve chemical changes? check all that apply.

leaving a copper penny in vinegar until it turns green
boiling saltwater for several minutes until only solid salt remains
extracting iron filings from a sand mixture using a magnet
crushing a rock with a hammer to extract mineral deposits
putting an iron nail outside for a month and observing changes

First one and last one on edge

Explanation: These are considered chemical changes because of reactivity whereas the other ones still have the same chemical properties just different physical appearances

cell differentiation  is how generic embryonic  cells  become specialized  cells. this occurs  through a process called gene expression. gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a  cell  functions.

explanation:

a skateboard rolling across the street - apex