Answer to Question 1
The student drawings should show individual yellow particles and blue particles. We can imagine that if there were billions and billions of tiny yellow particles (black circles in my drawing) and blue particles (open circles) in the drawing below that our eyes would not be able to distinguish between them and they would blur together as one color.
Answer to Question 2
Observations: We see swirls of brown coming out of the tea bag and mixing with the water. We also smell and taste the tea particles throughout the water.
Explanation: The particles of tea are able to leave the tea bag through the macroscopic holes we can see. As they leave the tea bag, they spread out throughout the water. Of course, the sub-microscopic particles of tea are not individually visible in the water, but are observed on the macroscopic scale due to the collective effect on the color, smell, and taste of the water.