Which of the following levels of organization is the smallest? kingdom species family genus

The correct answer is: [B]:  "species" .

Note:

In sequential order, from largest to smallest:

"Kingdom --> Phylum ---> Class ---> Order --> Family --> Genus --> Species".

Note:  This is one of the many "mnemonic devices" used to remember this sequential order:

"Kings Play Chess On Fine Grained Sand."

Neurotransmitters are messengers responsible for communication between neurons. they are released from synaptic vesicles and are received by receptors.  the communication is referred to as neurotransmission. the following statement is true about neurotransmitters: a. they're stored in synaptic vesicles in the axon.