Technological advances had helped reveal that the ocean floor was not flat, as once believed, but instead was marked by 50,000-kilometer-long, 3,000-meter-high ridges and 11-kilometer-deep trenches. How do scientists explain why, if new crust is constantly being formed from volcanic materials at the ridges, Earth's crust stays the same size?

A) Seafloor spreading is the cause of new crust being added. Old crust crumbles and forms mountains throughout the Earth's surface. Mountains keep growing.
B) Scientists hypothesize that new crust is the result of volcanic activity throughout the Earth's surface and older magma is destroyed as it subducts during earthquakes into Earth's mantle.
C) Scientists found that the youngest oceanic crust is located nearest the mid-ocean ridge and divergent boundary and the oldest crust is at subduction zones where it sinks back into the Earth.
D) Scientists found that the oldest oceanic crust is located nearest the mid-ocean ridge and forms from volcanic activity;the youngest crust is nearest the trenches and it comes from magma flowing up to Earth's surface..

By the late 1960s, scientists had developed the theory of plate tectonics based on a range of new evidence. Technological advances had helped reveal that the ocean floor was not essentially flat, as once assumed, but instead was marked by 50,000-kilometer-long (31,000-mile), 3,000-meter-high (9,800-ft) ridges and 11-kilometer-deep (7-mile) trenches. Scientists found striking patterns related to these features. They found that the youngest oceanic crust is located nearest the mid-ocean ridge and the oldest crust is nearest the trenches. They also detected a pattern of alternating magnetic polarity along the ocean floor, which emanated from the ridge tops. These two pieces of evidence, coupled with the fact that volcanic activity and island-building occurred most commonly at ocean trenches, suggested that new crust was created at mid-ocean ridges and destroyed at ocean trenches. Scientists Harry Hess and Robert Dietz used this evidence to revive and expand Holmes' convection theory into the theory they called "seafloor spreading." Finally, Wegener's notion of continental drift was coupled with a mechanism that could explain the movement of tectonic plates.

he this helps :D

Explanation:

1- in bradbury's  fahrenheit 451, all books are banned and burned upon discovery. in the nazi germany, books considered to be subversive to the regime would be burned to keep the population from generating ideologies that could challenge nazism.

2- was bradbury correct in his literal interpretation of  “where they burn books, they will also ultimately burn people.”? in some way, yes. when knowledge is not only limited, but also controlled, the people tied to it are led to their demise. just like in the novel, people in nazi germany who owned  subversive books were punished not only by the burning of their property, but also by the discrimination that followed after such a public form of consequence. if a person was seen being confiscated  subversive  books, they may be considered as an ally to the jews, which meant pretty much the same as being the enemy back then. because of the extreme exclusion and suffering that followed this punishment, it's almost like dying a slow death.

in this way, the phrase  “where they burn books, they will also ultimately burn people.” is both literal and figurative.

explanation:

mark brainliest and have a great day!