Se produce en la mitocondria. La respiración celular, como componente del metabolismo, es un proceso catabólico, en el cual la energía contenida en los sustratos usados como combustible es liberada de manera controlada.
I would say A. Because it seems like a logical explanation.
The correct answer is option C. Endocrine glands secrete hormones into the bloodstream because endocrine glands are ductless and the exocrine glands have ducts so they secrete their hormones into the ducts.