Answer:
4 sq. units
Explanation:
Because the vertices of S₂ are the midpoints of S₁, the area of S₂ will be half of that of S₁ which is 16 / 2 = 8. Similarly, because the same process is carried out on S₂ to make S₃, the area of S₃ is 8 / 2 = 4 sq. units.