Explain why we can sometimes see our reflection in transparents objects like glass and water. Detailed answer please :)

Select for each of the following statements whether it is correct or incorrect. (a) in an isothermal expansion of an ideal gas. (b) the temperature remains constant. (b) the pressure remains constant. (c) there is work done by the gas. (d) there is heat added to the gas. (e) the change in internal energy equals zero.

Only 3% of the water on earth is usable by humans. even though that 3% is through the water cycle, we still need to be careful not to waste water.

How long will a plane have to fly continuously with 1100 miles per hour in order to cover the same distance as that from earth to the next star, proxima centauri?