Which conclusion is best supported by Daniels observations and discoveries

Since there are no choices, it will be difficult to answer your question.

Let's say these are the choices:

A. The liquid is a pure substance because it is colorless.

B. The liquid is a mixture because its temperature rises.

C. The liquid is a pure substance because it remains liquid when cold.

D. The liquid is a mixture because it has a gas dissolved in a liquid.

your answer is D. The liquid is a mixture because it has a gas dissolved in a liquid.