The physical space between the presynaptic and postsynaptic neurons is called the
and the chemical that is released to signal across this space is called a

The physical space between the presynaptic and postsynaptic neurons is called the  synaptic cleft

and the chemical that is released to signal across this space is called a neurotransmitter

Explanation:

A synapse is the junction between dendrites of two adjacent neurons. Its function is to allow the transmission of nerve impulses from neurone to neurone. Tn the presynaptic knob there are vesicles which contain a transmitter substance which is usually acetylcholine. The acetylcholine diffuses from the presynaptic membrane to the postsynaptic membrane.

more words for this could be abiotic and biotic

abiotic: living organisms within an ecosystem

biotic: non-living organisms within an ecosystem

fumikage isn't really a bird, and tsuyu does have teeth. tsuyu has a transformation quirk which still allows her to be partially human. otherwise we'd have a large frog running around. fumikage has teeth because again, he isn't a bird. his head was a quirk mixture if i'm correct.