Answer:
Hormones act as first messenger but not as second messengers.
Explanation:
Second messenger act as signaling molecule which are secreted in response to various biological signals generated by first messenger such as hormones,neurotransmitters etc.Second messengers include various bioactive molecules such as cyclic AMP(cAMP),cyclic GMP(cGMP),inositol triphosphate(IP3),diacylglycerol(DAG),calcium ions(Ca2+) etc.
Hormones are extracellular signaling molecules whereas second messengers are intracellular signaling molecules.
The best and most correct answer among the choices provided by your question is the second choice or letter B.
Reptiles don't sit on their eggs like birds do because r<span>eptile eggs are not amniotic and have no shell, so sitting on them would crush them.</span>
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Valine, Leucine & Isoleucine
Alanine
Arginine
Glutamine
Lysine
Aspartic acid
Glutamic Acid
Proline
Cysteine
Threonine
Methionine
Histidine
Phenylalanine
Tyrosine
Tryptophan
Asparagine
Glycine
Serine
