Why does the earth have different layers?

The earth has different layers because as it formed, the lighter parts (like continental crust) floated to the surface, and the really heavy parts (like iron and nickel in the core) sank to the middle. It is just like when you mix oil and water: the oil will float to the surface because it is lighter (or less dense) than the water.

the right side of the picture going down is:

polymerase

protein

transport vesicle

modified protein

the left side of the picture going down is:

dna helix

single-stranded rna

endoplasmic reticulum

ribosome

golgi apparatus

protein released from vesicle

click to let others know, how is it

read more on -

answer; i believe that the correct answer is(d) nondisjunction during meiosis;