Answer:
D: 4.6 x
Explanation:
4.6 x 10^{9} = 4,600,000,000
Earth is approximately, 4.6 billion = 4,600,000,000 = 4.6 x 10^{9}
The skeletal system supports body structures; muscular system carries out the nerve commands to produce movement.
Hope this helps!
I think it’s (d) I’m really sorry if I’m wrong