Question

What do these two changes have in common

bleaching hair
saliva breaking down a piece of bread .

Select all that apply.
A. Both are only physical changes.
B. Both are caused by heating.
C. Both are chemical changes.
D. Both are caused by cooling.

Answer 1

Both bleaching hair and the action of saliva on bread represent chemical changes as they involve the creation of new substances with different chemical properties.

Step-by-step explanation:

The commonality between the two changes, bleaching hair and saliva breaking down a piece of bread, is that both are chemical changes.

Bleaching hair alters the hair's melanin, which chemically changes its color, while saliva contains enzymes like amylase that break down the starch in bread into simpler sugars, changing its chemical composition.

Neither of these procedures involves merely changing the physical form or appearance; instead, they create new substances with distinct chemical properties. Therefore, the correct answer is C. Both are chemical changes.