The bacteria in milk are destroyed when it __________ heated to 80 degree Celsius. A. would be B. will be C. is D. was

GATE 2017 · General Aptitude · Tenses · medium

Answer: 'Is' — simple present passive completes the zero conditional for a scientific fact. Answer: C.

1. Identify sentence type: The sentence states a scientific fact: bacteria are always destroyed at 80 C. This calls for a zero conditional (both clauses in simple present).
2. Check each option: A: 'would be' = hypothetical modal — does not suit a fact. B: 'will be' = future — sounds like a prediction, not a timeless truth. C: 'is' = simple present — correct for general truth. D: 'was' = simple past — implies a one-time past event.
3. Confirm the answer: Full sentence: 'The bacteria in milk are destroyed when it is heated to 80 degree Celsius.' Grammatically correct and scientifically sound.