adjective
No,concave part face plasma membrane.Convex part face endoplasmic reticulumn.
It all depends on whether you are inside or outside of the sphere.
The 'face' of the weld may be slightly convex, flat, or slightly concave.
It depends whether it's a concave or convex lens. If it's a convex lens - the thickest part is at the centre. With a concave lens, the thickest part is around the edge.
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
what part of speech is beneath
adverb
The part of speech for "explicit" is an adjective.
The part of speech for "lecturer" is a noun.
The part of speech for "rapid" is an adjective.