Answer:
The correct answer is - Trains can have inconvenient schedules, but produce less pollution than cars do.
Explanation:
Trains are expensive to build and also required land for making routes and stations and platforms for passengers but that can be reimbursed by fare in a longer time period.
Trains also produce pollution but in comparison to cars these are way less contribute to the pollution, However, these are not convenient as they start and reach at a specific time and also sometimes not comfortable like cars.
White blood cells fight disease
The substance is called DNA.
