The incorrect among the choices is "<span>direct signaling involves the activation of g proteins"
This is incorrect because direct signaling does not involve the activation of g proteins rather it involves the activation of ion channels resulting to either an excitation reaction (depolarization of the membrane) or an inhibition reaction (hyperpolarization of the membrane); and this will ultimately affect the action of the organ the nerve is innervating.</span>
I believe the correct answer from the choices listed above is the third option. It is oxygen that is a necessary reactant for cellular respiration to occur. Cellular respiration, in a sense, is breaking down sugar in the presence of oxygen. Hope this answers the question.
Fight or flight, because according to Hans Selye, this occurs at times of danger when your adrenaline is heightened.
Question:
<em>What is Darwin’s theory of the origin of species?</em>
Answer:
<em>The theory of evolution by natural selection, first formulated in Darwin's book "On the Origin of Species" in 1859, is the process by which organisms change over time as a result of changes in heritable physical or behavioral traits.</em>
Hope this helps!
