What is considered to be one-dimensional because it has lenth but no width or height

Witch one is it soo it the the question b.a,b,c,d

Which of the layers of the earth has the following three characteristics? i. it is made of molten rock. ii. it has currents that are constantly moving. iii. earth’s plates float on top of its currents.

Which types of seismic waves travel through earths interior? select all that apply. a) l waves b) p waves c) s waves