Spirilla are bacteria that can cause

a . into the substance, and the substance changed into a gas.

Explanation:

The correct answer would be that the scientists transferred energy into the substance, and the substance changed into gas.

Since the molecules of the substance are already in motion before the addition of energy, it means the substance is in liquid form as opposed to solid. Further addition of energy will result in the molecules of liquid moving faster and change phase into a gas.

The molecules of solids are stationary initially, addition of energy will result into liquid and not directly into gas, unless the substance has the capacity to sublime.

Hence, the correct option is a.