Answer:
the skill or process of taking photographs
Personally, I would address the problem, explaining to your audience that you've lost your "train of thought" from there, make fun of the situation, say "let's see, where was I?" * recieve an answer from audience * then continue one.
To sum it, make fun, and a light hearted joke about it, and continue to your best ability.
Despite the difficulties and circumstances in which the people live, they have not abandoned science because they are certain that they are the fruit of the future, with which they will change the present to a better future.
Give page numbers in the book from witch these are found.