If the producers in a food web were removed, the most likely change that would occur is:
The entire food web would collapse over time.
Producers, such as plants and phytoplankton, are fundamental to food webs as they convert solar energy into chemical energy through photosynthesis, forming the base of the food chain. Without producers, consumers (herbivores and carnivores) would have no source of energy, leading to a decline in their populations and ultimately causing a collapse of the entire food web.