Explanation

• "In plants, the cell signaling occurs through phytohormones": True. Phytohormones, such as auxins, gibberellins, cytokinins, ethylene, and abscisic acid, play a crucial role in plant cell signaling, regulating various physiological processes like growth, development, and responses to environmental stimuli.
• "Cell signaling is used to study the context of human diseases": True. Cell signaling is indeed used to understand the underlying mechanisms of various human diseases, including cancer, diabetes, neurological disorders, and many others.
• "Cell signaling is used to study the signaling between cells of an organism": True. Cell signaling is essential for understanding how cells communicate with each other to coordinate various physiological processes within an organism, including development, homeostasis, and responses to stimuli.

So, all three statements are true, making "All of the above" the correct answer!