Eggshells are made primarily of calcium carbonate. The acid in vinegar softens the calcium of the eggshell. Adding a little vinegar to the water when boiling eggs is an old cook’s trick that makes them easier to peel.
A link to this experiment is below in the comment box
Answer:
The answer is 5. Compound
The questions tha science can answer are those can be tested to try to find a definite answer.
For example, whether light is wave or particle is matter of science.
Questions that cannot have a definite answer are the field of religion or philosophy, and are out of the boundaries of science.
For example, does a criminal deserve the punishment of not seeing light? It is a moral question, which to be responded needs the intervention of philosophy and that could have different anwers at different times and in different societies.
A model showing that gases are made from the matter of particles that are too small to see and are moving freely around in space can explain many observations.