One of the processes that early manned space flights worked to perfect was known as “reentry.” This was the process

One of the processes that early manned space flights worked to perfect was known as “reentry.” This was the process by which the
space capsule (the black object above) broke away from the module and boosters and streaked through the Earth’s atmosphere
until landing back on the surface.
Reentry would have been much more dangerous if
OA. the Earth’s mass was much less than it is.
OB. the Earth’s atmosphere was much denser than it is.
OC.
outer space was slightly colder than it is.
OD. the Moon was farther away than it is.