Integrated TOEFL writing TPO 30

Reading and lecture are both about Greeks' defense against Roman navy attacks by a clever weapon called "burning mirror" by which Sun's rays onto Roman ships and led to set on fire. The author of the article believes that this story is just a myth and provides three reasons to support this claim. In contrast, the lecturer states that the author's claim is unconvincing, then she provides counterarguments to casts doubt on the points mentioned in the passage.
First of all, according to the reading, the author has mentioned that those mirrors with such capability of setting ships on fire require new sophisticated technology to be enough wide to have parabolic curvature. Thus, using this kind of advanced technology is so weird to exist in that period. However, the speaker points that ancient Greeks were using a single shield with polished copper had a parabolic shape to absorb Sun rays and directed into the ship and this issue was feasible to set on fire on the ship.
Secondly, the author suggests that setting fire by mirror is long-term work because if the device focusing Sun's light on wood, it takes at least ten minutes in 30 meters distance to set on fire, while object is immobile. So, due to movement of ship, this method is ineffective. On other hand, lecturer mentioned that fire could be initiated on not only on wood object that it had to be waterproof, but also there are other materials such as pitch which can catch fire very instantly and can be effective in that such circumstances while the ship is moving. So, as the second option it was effective.
Finally, the author states that the usual mean of setting fire on enemy's ship was fire arrows and it is reasonable in the same distance of mirror work. As the lecturer points, ancient people were familiar with fire arrows to use as a weapon, but the mirror was much more surprising and effective to attack than arrows.