Option 1: Bacteria and Protozoa: This option is incorrect. While bacteria and protozoa do play a role in the decomposition and breakdown of organic matter, they do not digest food before it enters the organism.

Option 2: Bacteria and Fungi: This option is correct. Both bacteria and fungi have the ability to externally digest their food. Bacteria release enzymes into their surroundings to break down food molecules, while fungi secrete enzymes onto their food source to break it down before absorbing the nutrients.

Option 3: Fungi and Protozoa: This option is incorrect. While fungi can externally digest their food, protozoa do not have this ability.

Option 4: Mucor and Rhizopus: This option is incorrect. Mucor and Rhizopus are both types of fungi, and therefore, only represent one group of organisms in the option.