The correct question would be "How much nutrient is there?" rather than "How many nutrients are there?"
The word "nutrient" refers to a substance that provides nourishment and is essential for organism growth, development, and maintenance. It is typically measured and expressed as a quantity or concentration rather than as a countable item.
Therefore, you would inquire about the amount or concentration of a specific nutrient present, rather than asking about the number of individual nutrients. For example, you might ask, "What is the concentration of glucose in the solution?" or "How much nitrogen is available in the soil?" These questions focus on quantifying the quantity or concentration of a particular nutrient.