Why were these liquids chosen?

The liquids chosen were saltwater, glucose and water.

Water: I think water was chosen because water is needed by all living things to live. If water bubbles is observed, or if the substance grew bigger, the substance might be a living thing. Thus water was chosen.

Glucose: I think glucose was chosen because it is a source of energy for many organisms, including humans. Some organisms only have enough energy to multiply and grow after consuming glucose. So if the substance multiplied or grew in glucose, it might be a living thing. therefore, glucose was chosen

Saltwater: I think saltwater was chosen because some organisms can only live in saltwater. For example, the clownfish would die if they were put into water and can only live in saltwater. Thus saltwater was chosen.