The answer to your question is B i believe
Answer:
cause at that time almost everything was natural nothing was a mixture of anything but now we don't know weather the thing is natural or not or is it mixed with something else also
for eg in earlier times fruits were grown naturally but now they r being injected to grow faster which is not natural and might cause us problems in future but the ppl in past didn't
It's asking you how did you understand what manipulate means by reading the sentence. Hope this helps
B is your answer I hope this helps
