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
The answer seems to be indeed A
The correct answer is D. This sentence is a perfect example of parallel structure because either after and before AND it in both cases uses simple past tense verbs which are LEARNED AND TRAVELED. The other sentences never show parallelism due to their units are never the same. For example, in letter A , it uses a verb in simple present WALKS AND a progressive tense verb which is TAKING. So, to sum up, for a sentence to be considered parallel, it must be coherent in its structure and internal words. They need to have harmony and unity in tenses as well.
