Ineed the definitions of: trench, rift zone, oceanic ridges, underwater mountain ranges, ring of fire, and fault. and what type of boundary is every single one.

trench-ditch

rift zone-is a feature of some volcanos

oceanic ridges-under water system

underwater mountain ranges-is a mid-ocean ridge 

ring of fire-is a area with volcanos and earth quakes

fault-planer rock fractures which show evidence of relative movement

answer: option d : 3.85 units

step-by-step explanation: in the given figure the blue line is diameter   .the diameter is the blue line which equals 7.7 units.radius is half of diameter .radius = 7.7÷2=3.85 units.

option d is the right answer.

explanation:

mark brainliest and have a great dayz1

c. seafloor spreading occurs.

d. crust becomes molten rock.

e. denser plates slide under lighter plates.