There are no major nutritional differences observed in organically and conventionally grown vegetables.

The answer to that question would be false as there are major differences between how the food grows as in growth rate, mass, and texture and taste; and what kind of nutrients and chemicals you'd be putting into your body such as conventionally are like GMOed for various reason to make certain characteristics while you maybe also eating chemicals produced thereof because of so that isn't necessarily healthy for you to consume whereas organically grown produce is likely to be smaller and disformed at times, and don't always have abundant crops with the acasional bug. So to answer your question Yes there are major differences between organically and conventionally grown vegetables.

That is true tge cactus as a structural adaptation to its envirinment has it leaves reduced to spines. but this doesnt mean it cant produce food it produces food because of the presence of chlorophyll in its stem