If you use more than one independent variable at a time, and will observe a change, you will not know which variable contributed to a changed result.
B. is correct. Let's look at the others...
A-- we know salt deposits are not alive.
C-- True, salt deposits are not alive, but they do not respond to stimuli... this is a characteristic of living things.
D-- Salt deposits are not alive and do not maintain homeostasis.
Answer:
its D it is used as a sweetner
Adrenaline, Cortisol, Norepinephrine.
Answer:
It's A I think it's the only that makes sense