One
substance, other than the secretions from nerve cells, that is used in cell
communication are hormones.
<span>
To
add, <span>a hormone is any member of a class of signaling
molecules produced by glands in multicellular organisms that are transported by
the circulatory system to target distant organs to regulate physiology and
behaviour.</span></span>
A I’m pretty sure because it base doesn’t even relate really, and weak acid doesn’t make sense
I'd say C. an allergic reaction. Mainly because lots of people are allergic to many things and many people intend to have seasonal allergies cause by plants. Hope it helps!
