Essential amino acids refer to the eight amino acids the adult body needs, which they cannot be synthesized correctly or at all.
The essential amino acids must be obtained from food such as proteins (meats, seafood, milk, eggs, etc).
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.
An object in motion needs less force
to continue moving because the inertia or the resistance to change in motion
was already overcome and the sliding friction that opposes a moving object is
also lesser. Therefore, <span>it is easier to
move an object at constant velocity as you only need to overcome the resisting
forces of the object.</span>
Capillaries<span> are </span>small<span>, thin </span>blood vessels<span> that connect the </span>arteries<span> and the veins. Their thin walls allow oxygen, nutrients, carbon dioxide and waste products to pass to and from the tissue cells.</span>