What is the oxidation number of an element? PLz help. Will give brainliest to correct answer. explanation helpful but not required. Dont answer unless you know

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

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.

When did stem cell research become known ? who discovered stem cell? what experiments or studies have been conducted so far?