Why is rain likely when warm, moisture-laden air meets cold air? A)The lighter warm air will rise and cool down, causing condensation and rain. B)The cold air moves faster and pushes the warm air away, causing condensation and rain. Eliminate C)The moisture in the warm air condenses on contact with the cold air, causing rain to fall. D)The cold air mixes with the warm air, reducing its temperature causing moisture to condense.

B) The cold air moves faster and pushes the warm air away, causing condensation and rain.

there is none because earth is stationary and flat.

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.