Final answer:
The ratio of 1 ml of water to 1 ml of pollutant is 1:1 because the quantities are equal. The correct option is A.
Step-by-step explanation:
If you have 1 ml of water mixed with 1 ml of pollutant, the ratio of the water to the pollutant is 1:1. This is because the two volumes are equal, and when representing ratios, the comparison is made between the quantities of each substance in a mixture. In this case, since there is exactly the same amount of water as pollutant, a straightforward ratio of 1:1 is used.
To understand this concept further, in the health sciences, ratios are often used to express concentrations of solutions. For instance, a ratio of 1:1000 would mean there is one part of a substance for every 1000 parts of the solution. In the context of our question, since there's an equal ratio of water to pollutant, we don't have such a large scale, so we use the simpler 1:1 ratio.
It's important to distinguish between different measures like ppm (parts per million) and molarity, which relate to the concentration of a solution. For example, ppm is a way of expressing very dilute concentrations, indicating the number of parts of a substance in a million parts of the total solution. However, in the provided scenario, we are not dealing with such a dilute solution, and therefore the ratio remains 1:1.
Ultimately, when we are mixing volumes of two substances, we just compare the volumes directly to find the ratio, unless asked to express it in a different unit or scale such as ppm.