What can the reflected wave tell you about the surface

atomic = no of protons.

mass number-atomic number = neutron number

i think it’s a. this is because if they measured the mass of something with a mass of 150g, then their final answer would have to be approximately 150g. though all of their answers are almost 150, rosa and tran have the closest answers (or the exact answer) to the accurate one.

the total distance traveled by the car is

30km + 49km = 79 km .