When a neutral metal sphere is charged by contact with a positively charged glass rod, the sphere (1) loses electrons (2) gains electrons (3) loses protons (4) gains protons

Charging something electrically involves the exchange of electrons (not protons)  so we're left with choices (1) or (2).  Since the sphere is neutral and the rod is positive, there will be a distribution of positive charge.  This can only be due to a lack of electrons, since electrons are negatively charged.  Therefore, the sphere must lose electrons to the positive rod, (choice 1) leaving both with a net positive charge.  The rod will be less positive than before, as will the sphere.

Amethod of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.

You will hear a hissing sound because of the carbon dioxide escaping the can or bottle