What do the words "distance", "force", and "work" have to do with each other?

The experiments with static charges were done by:

Tungsten-filament lightbulb emits light based on the temperature of the filament. which phenomenon does this demonstrate?

In which situation has the independent variable for the experiment been changed? check all that apply. changed from counting the number of duckweed at day 0 and day 14 to counting them every day changed from testing duckweed growth in beakers to testing duckweed growth in large outdoor tanks changed from testing the effect of ph on duckweed growth to testing the effect of light levels on duckweed growth changed from testing the effect of acid ph on duckweed growth to testing the effect of basic ph on duckweed growth