11) mWhich of the following sets of three units are all metric measurements of length?*
A) inch, foot, yard
B) kilometer, centimeter, millimeter
C) kilogram, gram, centigram
D) kilometer, foot, decimeter

insects!

explanation:

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me

305.7

explanation:

density =m/v

density =917/3.00

density = 305.

approximately = 305.7

in four significant figures