How does a mass drive work? A.
It uses the potential of a spacecraft to nudge an NEO out of its current path.
B.
It removes and ejects mass from an NEO, and gives it a little push.
C.
It involves a small rocket thrust; the mass of the NEO provides the momentum to move it further.
D.
It drives a smaller NEO into a collision course with the hazardous NEO.

The rearrangement of particles in a physical change. hope this

Domain eukarya; kingdom plantae should be the answer.

If its history of, then b) because a) implies only present day (now)

If the heat engine is a perfect carnot cycle engine, thenefficiency = (t2-t1)/t2   where t1=temperature of cold reservoir ( ° k) = 135            t2=temperature of hot reservoir ( ° k)   = 325thereforeefficiency = (t2-t1)/t2 = (325-135)/325 = 0.5846 = 58%  note: this is the theoretical maximum efficiency of a perfect heat engine.   real-life engines do not achieve this value.