Please check my answer:

Place the numbers in descending order.

2.3 × 10−10 ; 3.2 × 10−10 ; 2.3 × 10−12 ; 2.3 × 10−8...

(3.2 × 10^-10 ; 2.3 × 10^-10 ; 2.3 × 10^-8 ; 2.3 × 10^-12)

Your answer is incorrect. Here's the correct order in descending order:

2.3 × 10^-8 ; 3.2 × 10^-10 ; 2.3 × 10^-10 ; 2.3 × 10^-12