Any two substances whih are tasteless

Taste comes from the stimulation of chemical receptors in nerve cells on the tongue by particular chemical structures of substances. If there are no chemical structures pertaining to any of the chemical sensors, the substance would appear to be tasteless. All of these chemicals interact with the sensors with the help of the medium of saliva which has a lot of water. For example: the salt sensors might be susceptible to ions and the sweet sensors might be susceptible to hydroxyl groups on the sugars.

Now, taste is not a very precise field of study. A same substance may taste subtly different to different people. Can we be sure that water has no taste? The chemical sensors are always exposed to water. It might be that there are no sensors for water. It might also be that the signal for water is negated as a background signal. If water did have a particular taste, one thing is for certain, we would be tasting water in every bite of food and even at times when we are not eating as we always have saliva in your mouth.

Hope this helps, have a wonderful day/night, and stay safe!

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.