A
1 only
B
2 only
C
1 and 3
D
2 and 3
Correct answer: (c) 1 and 3
Explanation
- A
1 only
1 only. Lactose digestion (lactase-positive strains) is also keyed.
- B
2 only
2 only. Many probiotic organisms are native gut commensals; statement 2 is false.
- C
1 and 3
1 and 3. Bacteria and yeasts (e.g. Saccharomyces boulardii); they help digest milk sugar. They do occur in the gut.
- D
2 and 3
2 and 3. Statement 2 fails.
Summary. Official key is (c) 1 and 3. Probiotics include bacteria and yeasts. They are not ‘only in food, never in the gut’. Some strains help digest lactose.