Which box has fewer objects? Explain your answer.

Here are the boxes with fewer objects:

a)
The left box has 5 stars.
The right box has 3 moons.
Since $3 < 5$, the box with the moons has fewer objects.

$$\boxed{\text{Right box (moons)} \quad \checkmark}$$

b)
The left box has 2 wavy lines.
The right box has 5 straight lines.
Since $2 < 5$, the box with the wavy lines has fewer objects.

$$\boxed{\text{Left box (wavy lines)} \quad \checkmark}$$

c)
The left box has 7 arrows.
The right box has 4 spirals.
Since $4 < 7$, the box with the spirals has fewer objects.

$$\boxed{\text{Right box (spirals)} \quad \checkmark}$$