When a candle is cooling down is it a physical or chemical change

How will the emission of an alpha particle affect the atomic number of an atom

What is the independent variable in this investigation? mass volume sample number substance density

An animal cell loses the ability to convert energy stored in food to energy that the cell can use. which of the cell's organelles has stopped working? a.the mitochondria b.the nucleus c.the vacuoles d.the endoplasmic reticulum