Complex sentence: He believed that biotechnics was the emerging answer, then, the only hope that could be set out against the problem of megatechnics, an answer that, he believed, was already beginning to assert itself in his time.
Split into simpler sentences: He believed that biotechnics was the emerging answer and the only hope that could be set out against the problem of megatechnics. It was an answer, he believed, that was already beginning to assert itself in his time.