How does the ocean floor preserve evidence of past magnetic reversals.

(A) The ocean floor is uniformly old, preserving the Earth's 4.6 billion history.

(B) Isotopic analysis of ocean core sediments help determine sea floor age and this can be used to infer past magnetism.

(C) Magnetic particles in basalt orient with the magnetic field in force at the Curie Point.

(D) Mantle hot spots are always oriented to the magnetic field.

Samir watches a 100-minute movie on his spaceship. maria's spaceshipe flies in the same direction as samir's spaceship but she observes his move to last 125 minutes and his spaceship to be 40 m long. how long does samir observe his own spaceship to be? according to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does marias voyage take according to samir?