Pls give a detailed explanation about what is genetic variation

How air particles exert a pressure on the inside of the balloon

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 have the greenhouse gasses increased from the year 2000 to 2018