Need help with the use of "the"

Question

Why do we say "rise in demand" instead of "rise in the demand"? Is this logic also applicable for phrases such as "increase in adoption" and "increase in demand"? Please assist. Are these idioms??

Answer 1

"Demand" is an uncountable noun, and it's referring to a general concept in this instance, so it doesn't take an article. If you were talking about a specific type of demand, like "rise in the demand for wheat", then it does take an article.

See this related question for more details.