A)it involves the release of chemical signals.
B)it involves the use of receptors.
C)the signal is contained within a single cell as it travels the long distance.
D)it relies on the blood to carry the signal from one cell to the next.

A)relative half-life (3 or 4 hours).
B)number of tyrosine molecules linked together.
C)number of iodines which are found on the hormone.
D)number of enzymes required to synthesize the hormone.

A)In paracrine communication,the target cell receives chemical messenger from signal cell via diffusion.
B)A neurotransmitter is a chemical messenger that had been converted from an electrical signal.
C)Endocrine messengers are hormones.
D)Allelochemicals are chemical messengers released into the external environment by individuals of the opposite sex but of the same species.