Why is Earth's outer core hotter than Earth’s oceanic crust?

1 Earth’s oceanic crust is denser than Earth’s outer core is.
2 Earth’s oceanic crust has lava flowing from the mantle.
3 Earth’s outer core has a composition of solid iron and nickel.
4 Earth’s outer core is deeper within Earth than oceanic crust is.

the first one

Explanation:

that's a true information

it might look like that the ideal way to research the health effects of trans fats is through a controlled experimental feeding trial. but these kinds of trial have several important limitations that the researcher must look into:

short in duration (this factor usually checks up on the intermediary risk factors rather than the actual outcomes of the disease)

limited dietary changes

only makes use of healthy participants