What causes leaves to chsnge color in the atumn? is it a chemical or physical change?

Astudent carefully transfers 30 g of water and 30 g of alcohol in a glass tube, forming two layers and filling the tube completely. after sealing the tube, the student mixes the solutions, and notices a bubble that forms in the tube. what is the mass of the contents in the glass tube after mixing?

How does the principle of electromagnetism explain the interaction between earth’s magnetic field and the solar wind?

Why is retrograde motion an apparent motion