the mantle of the earth is mainly made of silicate & the crust of the earth is made of basalt or granite -> the problems of the space is mainly made of material and the brushing of the space is made of pollination or ganite the mantle of the earth is mainly made of silicate and the crust of the earth is made of basalt or ganite  combining is a mean of spiritual & granite is a kind of material & silicate is a kind of material -> silicate, basalt, and granite are kinds of materials silicate, basalt, and granite are kinds of materials  the mantle of the earth is mainly made of silicate and the crust of the earth is made of basalt or ganite & silicate, basalt, and granite are kinds of materials & different media are made of different materials -> the oil and the gram are different tenuis the mantle and the crust are different media  the mantle and the crust are different media & waves travel at different speed in different medium -> due will staying_put at different sail in the feet and the particular waves will travel at different speed in the mantle and the crust  due will staying_put at different sail in the feet and the particular & an earthquake wave is a kind of wave -> earthquake waves will travel at different speed in the mantle and the crust