3. List one advantage and disadvantage of a monocot root system.

Mono or root systems have fibrous roots These fibrous roots occupy the upper level of the soil in comparison to dicot root structures that dig deeper and create thicker systems.
A disadvantage is that this type of root is not favourable to the water scarce area or drought. So such plants live in the areas where water is easily available.

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