Answer:
The egg is the dependent variable and the salt is the independent variable.
Explanation:
The dependent variable is something that stays the same throughout the experiment. The independent variable is something that might not stay the same throughout the experiment. The egg does not change because we're using an egg and not an egg and then a tomato or a potato, but the salt does change because we're changing the amount of salt in the bowl/plate or anything else that we are using to perform this.
This is kinda long but it explains mostly everything. DM me for more dependent and independent variable help.
