A. The aerialist’s feet and the rope
Light is consist of different spectrum of colors called wave lengths. The colors that visible to the naked eye are known as Red, Orange, Yellow, Green, Blue, Indigo, and Violet. These colors are arranged from shortest to longest. The color red that appeared from the other side of the tank signifies that the wavelength that can only pass through the material is red, which is the shortest. Other wavelengths are dispersed into the molecules of the glass, hence it cannot be seen through the other side.
a) Cumulus is 100% the correct answer
If you have no way to accurately measure all of the object's bumps and dimples, then the only way to measure its volume is by means of fluid displacement.
-- Put some water into a graduated (marked) container, read the amount of water, drop the object into the container, and read the new volume in the container. The volume of the object is the difference between the two readings.
-- Alternatively, stand an unmarked container in a large pan, and fill it to the brim. Slowly slowly lower the object into the unmarked container, while the pan catches the water that overflows from it. When the object is completely down in the container, carefully remove the container from the pan, and measure the volume of the water in the pan. It's equal to the volume of the object.
