It would be the skin
There is five parts of an apple skin meat core seed leaf
The Earth's crust is like the skin of an apple because it is the outermost layer of the Earth, just like the skin is the outermost layer of an apple. Both the Earth's crust and the apple skin serve as a protective layer, shielding the inner parts from external influences. Additionally, just as an apple's skin can vary in thickness and texture, so can the Earth's crust in different regions.
An apple's skin has vitamins and flavonoid called "quercetin" that prevents wrinkles from forming. Aside from that, apples are also known to help avoid heart diseases. As the saying goes, "An apple a day keeps the doctor away". This is true. So, keep eating those apples.
An apple (red or other) is a fruit, of which only the 'juicy' part is acidic, like most fruit juices.The 'dry solid' part (fibres, 'flesh', skin etc.) of an apple does not have a pH value, so no acidic or alkaline properties.
The edible part, because the "lower layer of the atmosphere" would be the troposphere that takes 75% of the mass of air in the atmosphere itself. The core is the earth, and the skin is the rest of the atmosphere.
The skin and meat of the apple is the part to eat. The seeds and core are to be avoided. The seeds are known to be sources of cyanide.
There is five parts of an apple skin meat core seed leaf
Skin, core, seeds, meat and stem.
The skin
the skin and the white part. not the core
The part of the fruit under the skin but outside the apple core.
That would be the skin, if you were comparing that apple to the Earth.
The thin skin.
because they have the same layer the crust which is the skin of an apple the mantle the white part of an apple and the core which is the seed of an apple.
Apple with no skin
skin that comes off an apple
Both are equally as important and its always better to eat an apple with the skin on! :)