Question

1. which change can be reversed by physical means?

a. burning wood
b. rusting iron
c. dissolving sugar
d. digesting food

Explanation:

Physical changes can be reversed by physical means, while chemical changes (which form new substances) cannot. Burning wood, rusting iron, and digesting food are all irreversible chemical changes. Dissolving sugar is a physical change: the sugar molecules disperse in water but do not change chemically, and the sugar can be recovered by evaporating the water (a physical process).

Answer:

c. Dissolving sugar