Name three plant-like organisms which cannot produce their own food.

Pretty much all plant organisms can produce their own food. However, organisms like mushrooms are often confused for plants, but they CANNOT make their own food.  

Mushrooms are fungus, meaning that they have to get their food from other dead or decaying organisms. This makes them different from both plants and animals because they don't eat food, but they don't make it for themselves either. They absorb it through their roots.