Infer why obsidian which is black or red in color can have a granitic composition

Obsidian is an igneous rock that forms in the same way a granite forms, so their silica content is also quite same. When hot magma that are highly rich in silica and which are highly viscous because of its high silica content, comes out to the surface after eruption, it undergoes fast cooling, as a result of which the crystals do not get much time to form larger crystal. So they contain smaller crystals. And this dark variety of obsidian such as red or jet black is due to the presence of iron oxides such as hematite and magnetite.

Thus, obsidian and granite has a similar composition and both are igneous rocks.

there are 35 white marbles

step-by-step explanation:

y- yellow marbles

4y + 5 = 45

subtract 5 from both sides

4y = 40

divide for from both sides

y = 10

plug in 10 to get 40 yellow marbles then subtract by 5 to get 35 marbles

thus there are only 10 yellow marbles

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.