Describe some tests that could be done to determine what an unknown substance is.

Simple chemical tests can be used to identify the presence of various elements or classes of molecules (Tollen's test). ... Electron spin resonance (ESR): Also referred to as electron paramagnetic resonance (EPR), this method uses the spins of unpaired electrons in molecules to determine structure

layer a is the exosphere and layer b is the thermosphere.   is the answer i think but i hope this .

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.