According to the endosymbiotic theory of the origin of eukaryotic cells, how did mitochondria originate? From engulfed, originally free-living bacteria
When a protoeukaryote engaged in a symbiotic relationship with a protocell by secondary endosymbiosis
From the nuclear envelope folding outward and forming mitochondrial membranes
From infoldings of the plasma membrane, coupled with mutations of genes for proteins in energy-transfer reactions

answer:   option a) glucagon was secreted by his pancreas before he ate the cookies because blood glucose was low. insulin was secreted after he ate the cookies because his blood glucose was high.

explanation:

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.