These people help with the motion of the bicycle and predict the forces that it will endure. a.
Engineers
c.
Chemists
b.
Physicists
d.
Carbon Producers

explanation:

since the crust is readily accessible, scientists have been able to perform hands-on experiments to determine its composition; studies on the more distant mantle and core have limited opportunities samples. so scientists also rely on analyses of seismic waves and gravity and as well as magnetic studies.